Where's the TM Flash in White?

Question

I would like to have it to get through Mistralton Cave and Wellspring Cave (basement).

Answer 1

There is a man on Castelia City's second street from the left (Narrow Street). When you pass the dumpster, he'll stop you and give you TM70 (Flash).

Answer 2

Go on narrow street in castellia city and a guy jumps out by the dumpster and gives you the tm