Roswell Conspiracies: Aliens, Myths and Legends S02 E03 "Amok Vampire"

S1, E23: Valra, a renegade Vampire, acquires a taste for Banshee blood when she bites Sh'lainn and eventually drains her, mutating them both into Vamp/Banshee hybrids. Valra uses her newfound power and influence over Sh'lainn to turn her against Nick and to try to overthrow Hanek and INTRAcom. Now the Alliance and Hanek must work together to stop Valra.