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To complete the Dragon's Lair mission, you must talk to Glint after defeating her six facets, one for each core profession. Each of these facets is in its own area which has its own distinct disadvantage. At the end of each area, you must defeat the facet, which opens a portal to the next area. Note that every facet has an elite skill that can be captured, so you may want to bring two Signets of Capture on this mission. The mission takes some time to do, but it is not very difficult and can be done easily with henchmen.

At the beginning of the mission, you will find yourself in a small crystalline chamber with one Forgotten Gate Keeper. Talk to him to have him open a portal. Proceed to the first area.

Facet of Light
While you are in this area, all party members will be under the spell Domain of Health Draining and suffer a Health degeneration of −3. This will put your healers under constant stress, so advance carefully and give them time to actually heal. You will encounter solitary Forgotten Sages and pairs of Enchanted Swords and Enchanted Hammers here. Defeat the Facet of Light to open a portal to the Facet of Nature.

Recommended skills: Well of Blood provides partywide regen, and Recuperation at high Restoration Magic will completely counteract the degen, though it must be resummoned whenever the party moves. Heal Party helps to counteract it by healing everyone, and Light of Deliverance works fantastically here, as it costs little energy and is relatively spammable.

Tip: About midway down the ramp right before the ice (where you fight the facet) the degeneration is not active! Try to keep your whole party here to heal up before the big fight.

Facet of Nature
Here you will be under the influence of Domain of Slow, which will decrease your movement speed. You have to fight your way through trios of Enchanted Bows and pairs of Enchanted Swords and Hammers. Defeat the Facet of Nature to open a portal to the Facet of Chaos

Facet of Chaos
In this area, you will not be under the influence of a permanent effect. Instead, you will have to deal with the fact that the Crystal Spiders you will encounter in large numbers have the skills Shatter Enchantment , Shatter Hex and Hex Breaker. There are areas that are divided from the main path by clear crystal walls. Behind those walls, pairs of Forgotten Illusionists wait for players to come too close. It is possible to cast spells that don't have a projectile through those walls. Similarly, the chamber at the end of this area is divided by many low walls, allowing spellcasting and ranged attacks. Melee fighters will have to run around the obstacles; be careful not to aggro too many enemy groups at once when doing so. Defeat the Facet of Chaos to open a portal to the Facet of Darkness.

Facet of Darkness
Here you will be under the effect of Domain of Energy Draining. Everyone will suffer from Energy Degeneration of −1. In addition, everyone (both players and enemies) will be enchanted with Death Nova at Death Magic 0. You will encounter Forgotten Cursebearers and Rock-Eater Scarabs. Defeat the Facet of Darkness to open a portal to the Facet of Elements.

Recommended skills: Dwayna's Kiss and Healing Light benefit greatly from all players being under enchantments at all times, and help counteract the energy drain by being more efficient or refunding energy.

Tip: Even if Death Nova is removed via Enchantment removal, it will be reapplied in a few seconds. Use this to your advantage with skills like Shatter Enchantment. Also note that Death Nova renders the elite skill of the Forgotten Cursebearers you will find in this area (Order of the Vampire) useless.

Facet of Elements
Here you will encounter Forgotten Arcanists and Crystal Guardians, powerful Earth Elementalists. Ward Against Elements is quite useful in this area, as the enemies deal only elemental damage. Watch the nearby pairs of Arcanists when attacking a group of Guardians; they will often attack you from behind while you are engaged in a fight. There are also areas in this facet where the elements are going crazy; you will be bombarded by effects similar to Elementalist spells while passing through (the circles cycle between Eruption, Fire Storm, Maelstrom and Chain Lightning before going inactive and restarting). These areas are easily recognizable by their glowing circles (similar to Elementalist's Wards). Obviously, you should not stay inside those areas while fighting; leave them as quickly as possible. Defeat the Facet of Elements to open a portal to the Facet of Strength.

The environmental effects share the names of spells, but they have different icons and descriptions (which simply say "Spell: (<effect name>)":

Eruption: 35 damage per second vs AR 60 and blindness (unknown duration, only occurs AFTER the Eruption ends, like the old version of Eruption)
Fire Storm: 32 damage per second vs AR 60
Maelstrom: 35 damage per second vs AR 60 and interrupts spells
Chain Lightning: 71 damage vs AR 60 at the start of the animation, no effect afterwards

Facet of Strength
Every player (including spirits but not monsters) will be knocked down every 20 seconds for 5 seconds while in this area. Warrior skills that prevent knockdown (like Dolyak Signet or Balanced Stance) are very useful here. You will have to fight pairs of Enchanted Swords and Hammers. There are also groups of one Enchanted Sword, one Crystal Guardian and three Crystal Spiders; these can usually be avoided. Defeat the Facet of Strength to open a portal to Glint's chamber.

Recommended skills: Ward of Stability provides immunity to knockdowns for all players within it. Also, Supportive Spirit might have some use, as monks can predict when the next knockdown will be, and support players likely to be attacked while knocked down.

Note: If you skip this cinematic, you will miss an important part of the story. Unlike the six previous cinematics, where all that is seen is the party walking through the portal, this time Glint will explain what is going on, so you may want to watch it.

Glint's Chamber
When you have arrived in Glint's chamber, you have finished the mission. You can either end it by walking through the portal, which will take you to Droknar's Forge, or try the mission bonus.

Bonus

After you meet Glint, do not go through the portal. Instead, pick up a Dragon Egg. Enraged, Glint will turn hostile. Defeat her to complete the bonus. Should you fail, do not worry; she will resurrect you and send you to Droknar's Forge anyway.

Glint's Skills
Glint has a set of very powerful monster skills that you have to deal with:

Crystal Haze is a hex that can cause a massive energy shortage. Because this is an AoE hex, your entire party will be affected by Crystal Haze. She likes to cast it at the very beginning of the battle.

When Glint's health drops to about 50%, she will cast Crystal Hibernation, which gives her +7 health regeneration and converts all non-physical damage dealt to her into healing for 20 seconds. However, this skill has a relatively long activation time, so it is easy to interrupt.

During the fight, Glint will activate her Jagged Crystal Skin stance. When hit with a physical damage, it will deal 100 damage to nearby foes. This skill can be very devastating, but can easily be overcome by everybody dealing elemental or other non-physical damage. The easiest way to achieve this is removing it with Wild Blow. An alternative is to get someone who captured Greater Conflagration later in the game and bring it to bypass the Physical Damage Requirement.

Glint may also use Crystal Bonds, so don't rely too heavily on enchantments when fighting her.

Note, after a while, when she drops below 50% health, Glint will stop using her skill Jagged Crystal Skin. After this, the damage she can deal will be drastically reduced against the warriors and other close range fighters in your group.

Additionally, even though she is not technically a boss, the durations of hexes and conditions inflicted on Glint are halved.

Defeating Glint
When assembling a party to take on Glint make sure everyone understands his or her role. At minimum, your party should have the following:

One or more solid tank. This player should position himself right next to Glint, before someone else picks up the dragon egg to trigger the bonus. He or she should maintain her aggro to protect his or her more fragile team members from Glint's vicious attacks. He or she could also bring interrupting skills to help prevent Crystal Haze and carry Wild Blow to easily get rid of Jagged Crystal Skin.

One or more hex removers, who get rid of Crystal Haze. Pre-casting Holy Veil on key party members is a good idea, other than that Inspired Hex (or Revealed Hex) works best; it can be reused immediately as Crystal Haze is a monster skill and won't replace it.

You should of course also bring one healer and/or protection monk. The rest of the party should focus on dealing as much damage as possible. Because of Glint's high level and armor, health-degeneration and armor-ignoring damage works best. This is especially pertinent if you choose not to interrupt Crystal Hibernation.

Other helpful roles:

A blood necro with Grenth's Balance can do major damage by shedding some Health with sacrifice, then using Grenth's Balance. See the skill's page for more detailed instructions on proper use.

Blindness, Weakness, and hexes that decrease the target's attack speed or cause the target to miss can be used to reduce Glint's offensive power.

Rangers with Burning Arrow do well against Glint; combine with Necromancers using Virulence.

If you don't want to use Wild Blow or other stance-ending skills, consider bringing the Ranger elite Greater Conflagration, which converts all physical damage to fire damage. This allows you to ignore Jagged Crystal Skin. The same result could be achieved if all party members use weapons that do not deal physical damage, for example a Warrior using a Fiery axe, a Ranger using a Shocking bow, etc.

A Mesmer with Wastrel's Worry can be a powerful ally while facing Glint. Due to Glint's half hex/condition duration (see Natural resistance), Wastel's Worry will trigger in 1.5 seconds. This allows the Mesmer to "spam" the skill almost constantly, inflicting massive armor ignoring damage to Glint.

Ritualists are a great help against Glint. The spirit of Shadowsong alone will keep Glint blinded almost permanently, thus rendering her nearly harmless. Shelter and Displacement will also greatly reduce the damage Glint can deal. Dissonance will interrupt Glint's Crystal Hibernation and other skills.

Taking an interrupter is useful but by no means necessary. When choosing interrupt skills, be aware that Crystal Hibernation is not a spell. Particularly useful is the skill Broad Head Arrow for Rangers, which causes Dazed and thus allows the party to easily interrupt Crystal Haze and Crystal Bonds. For a primary or secondary Ritualist Warmonger's Weapon is an ideal skill as it can interrupt multiple times and any skill or spell. This also means the party won't have to worry about carrying Hex removal.

Glint is slow and her ranged attacks have a considerable 'flight' time; run and strafe to avoid getting hit. They tend to take off at least a quarter (~175 or more damage) of a character's max health, regardless of class. Try to keep everyone above 50% health; use self-heals if the party's Monks are busy.

Everyone should bring a Resurrection Signet or other fast-casting resurrection skill, and use it immediately if a party-member goes down. There is no time for skills like Restore Life in this battle.

Note: Glint likes to stay in one spot; the entire party can sometimes retreat to safety for a rest break before heading back into the fray. The party will regenerate health faster than Glint can naturally, so this can give a slight advantage. This would also be a good time to resurrect any fallen party memebers with something like Rebirth, if everyone's Resurrection Signets have been used up.

Alternative 1
You may exploit the AI's reaction to several AoE hits on an enemy causing them to run away. Ignite Arrows constantly pressuring Glint, with additional Ignite hits from Dual Shot, Forked Arrow, Triple Shot, and Needling Shot, keeps her constantly running away. This will prevent Glint from dealing much damage with her attacks. However, you will still have to deal with her skills like described above.

Alternative 2
A Ranger-heavy team with lots of traps can greatly improve the odds of defeating Glint. Before picking up a Dragon Egg, everyone should lay as many traps as possible all around Glint. As soon as the battle begins, Glint will be hit with Burning, Crippled, Bleeding, Blind, and also Poison if Viper's Nest is used. Additionally, damage from Dust Trap ignores armor, which is quite useful versus Glint. Glint attacks and moves slowly, so it is more than likely that there will be opportunities during the battle to trap right under her.

Virulence and Fragility can be used for further damage. "Victory is Mine!" can be used for healing, if it's available. The elite skill Extend Conditions could also help, though it isn't a Prophecies skill.

With Henchmen
This bonus can and has been done with all-hench parties. Consider that Little Thom carries Wild Blow, and that Claude, who loves to spam Blood Ritual, carries Grenth's Balance. Also, with Alesia and Lina, you have a healing and a protection monk. Thus four of the roles described above can be fulfilled. The remaining party slots should be filled with Orion and Reyna for damage-dealing. Lastly, it is recommended to bring Dunham; he has Shatter Hex, Empathy, and Crippling Anguish, all of which are useful against Glint. He will effectively keep her snared and degenerating for the entire battle, and he manages to do very well in Hard Mode.

Stefan is not recommended, because he does not carry Wild Blow, and will thus be annihilated by Jagged Crystal Skin. Bringing Greater Conflagration would negate this point.
Hex removal is useful, but not absolutely necessary. Glint usually targets Alesia or Lina first. Once either dies and is resurrected by Resurrection Signet, Crystal Haze is gone, so healing proceeds as normal.
Note that even with an all-Henchman party, it is still not absolutely necessary to interrupt Crystal Hibernation, although it certainly makes the battle easier.