Buffy's two vampire lovers, Angel and Spike, join forces for the first time since they tried to end the world in order to thwart a threat from their dark past.

Spike discovers that someone has put a hit out on him, and sets out to find this person or thing. The trail leads him to LA, where Angel is enmeshed in a case involving a stolen box from a museum. The box is one that Angel recognises from his brutal days as Angelus, as he travelled Europe with William the Bloody, a.k.a. Spike, in tow.

Now the two reformed vampires, both of them exes of the Slayer, must team up - albeit reluctantly - to find out who from their past is challenging their present.