Pokémon XD: Gale of Darkness/Cipher Lab

The Cipher Lab has a lot of battles and a lot of Shadow pokemon, so head back to town for supplies if you run low on stuff. Before you can enter the building, however, you must battle at least one of the Hexagon brothers. They each have a shadow pokemon, so battle them all if you want to get the Shadow Pokemon now instead of later.

The door on the right only has a couple of items in it, so grab them and take the door on the left, which has a heal machine and a PC. Then take the elevator in the back, but be prepared for an ambush...

Head east after you get out of the elevstor to reach an another elevator to take. This one drops you off even lower into the Lab. Battle the people you come across, grab the Peon's Shadow Spinda, open the chest for a Revive, and take the stairs.

Go south after climbing the stairs and, after the cutscene, continue further south to battle a guy with a Shadow Numel. After the battle you'll reach another elevator, take it.

After you get off the elevator, there is another elevator next to you that takes you to a healing machine and an Elixir, but it will be guarded by a trainer without Shadow Pokemon. Afterwards, go left, down, left to reach the next elevator; explore the rest of the floor for more items.

Exiting the elevator, you reach a room with more ambushes, first with a Peon carrying a Shadow Carvanha. Keep moving straight ahead to avoid another Peon without a shadow pokemon, but you'll miss out on the Full Heal. At the end of the hall you'll reach a room with Scientists talking to each other; you know the drill. Don't leave without examining the table, it has an ID Card on it, which is needed to reach Prof. Crane.

Take the north exit to the room and battle the Peon that ambushes you. take the elevator that follows by using your new ID Card on it.

Keep moving after going through the elevator to find Professor Crane and another Peon. Beat the shadow-pokemon-free trainer and bring the Prof. back to the top of the Lab. But you better save first.

When you reach the elevator that you used to enter the lab with at the beginning, you will be stopped by Cipher Admin Lovrina, who won't let you leave without a battle.

Cipher Admin Lovrina

Lovrina has four Pokemon; Luvdisk, Beautifly, Roselia, and a Shadow Delcatty. Use Fire or Flying on Beautifly and Roselia, and use whatever Pokemon you have that are the same gender as her other two since they use Attract. Work her down to just having Delcatty and try to capture it. If you don't, remember that you can get any missed Shadow pokemon back later on.

After the Admin Battle, grab the Data ROM that she drops and return to the Pokemon HQ. The Purify Chamber is ready for use now, so either take in the in-game lessons on it or you can read up about it here at Strategy Wiki's Purify Chamber Page. Go talk to Datan, who is outside, and he will tell you to bring the Data ROM to Pyrite Town; your next destination.