Basta leggere il Gatherer card ruling,del vampiro e della brainstorm. Se prendi come esmpio le meccaniche che si svolgono tra il vampiro e la brainstorm non dovrai rivelare le carte che peschi di brainstorm.
Vampire Nocturnus
Gatherer Card Rulings [Nov 2009]
* 10/1/2009: If an effect tells you to draw several cards, reveal each one before you draw it.
* 10/1/2009: If the top card of your library changes during the process of casting a spell or activating an ability, the new top card won't be revealed until the process of casting the spell or activating the ability ends (all targets are chosen, all costs are paid, and so on).
* 10/1/2009: To work as an evasion ability, an attacking creature must already have flying when the declare blockers step begins. Once a creature has become blocked, giving it flying won't change that.
Brainstorm
Gatherer Card Rulings [Nov 2009]
* 10/4/2004: This is all one effect. You draw 3 and return 2 cards all in one resolution. Nothing may happen between the two. If something triggers on drawing cards, it will go on the stack after Brainstorm finishes resolving.
[s]Poichè l'effetto della brain è unico devi considerare la 2a nota del vampiro.[/s]
EDIT by Kalle: no, risposta corretta di Drakoo sotto.

Referenze:
Luigigarz,benderCIMO,paolo84,rteyu, mawmaw,Kaiser_soze,devsho,Guido79,7filo7, feanor86, buzz82, mattavell, Sismo, Onikirimaru, invokeprejudice, Nicola, akenathon,FORCE OF WILL,Iso_90,Giappone,Jiaozy,DarkNinjaTech,bartbrat,Ale.F,Albyno76