Buffy the Vampire Slayer (1997)

S4E12 A New Man

Ethan Rayne makes his comeback to town, bringing chaos with him as he turns Giles into a demon. With their friend in peril, the group finds themselves in need of assistance, and to their surprise, Spike emerges as the only one capable of providing the help they desperately require. As tensions rise and time runs out, Spike must step up to confront the challenges ahead.