Avengers Tower (Borderless) [Marvel Super Heroes]

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Hero spell or to activate an ability of a Hero source.
{4}, {T}: Look at the top three cards of your library. You may reveal a Hero card from among them and put it into your hand. Put the rest on the bottom of your library in any order.