Things You'll Need
Instructions
Getting the Lugia Mission
Complete the game. To technically complete the regular game, you must complete the 14th mission. However, once the game is complete, there is still much to do and more to the story.
Reload your "Save" file after beating the game. There will be a cutscene, after which you must use your Latios to fly back to the third village you visited during the game.
Watch the cutscene in the village and you will be issued a new mission. To complete this mission, you must catch the three legendary birds, Articuno, Zapados and Moltres. Fly into the sky with Latios to find the birds, and follow them to their lairs to collect them.
Complete every quest and capture or see all 300 Pokemon. You only need to have their entries in your Ranger Browser and do not actually need to own them all.
Head to Rand's house, which is the house that was on fire in Mission 2. There will be a cutscene during which you are issued a final mission. This is also the mission in which you encounter and can get Lugia.
Getting Lugia
Follow the directions of the mission, which lead you to an underwater cavern.
Fight your way through the cavern and complete the underwater mini-game.
Confront the Blue Eye when you see it stuck under a rock and it will flee. Follow it all the way back to the surface of the water.
Fight the Lugia when you are attacked to weaken it. Draw circles around it with your stylus to capture Lugia as you would any other Pokemon. You will receive its sign and complete the main storyline of the game.