no all you have to do is get the three birds.(zapdos,moltres,and articuno) then talk to alakazam and he will tell you to go to their friend area.
at silver trench.
Lugia
Silver trench 99f
99
I don't know find out yourself
Lugia is in silver trench 99f size four ****
go to silver trench he is on 100F
after you recruit zapdos, articuno, and moltres.
Silver Trench has 99 floors, but you'll meet, battle and recruit Lugia on the 99th floor.
you must recruit articuno, zapdos, and moltres. go to their friend area they will give you a vertex gem silver trench is now unlocked
Silver Trench I think 40th floor
Silver Trench on floors 65 thru 79 be sure to bring a water pokemon + Hm Dive