What do you do when an old lover comes back? That's the question on 'CSI: NY' (Wed., 10PM ET on CBS).

[Spoiler alert.]

Mac Taylor (Gary Sinise) has had to make a lot of tough choices as head of his crime lab. But now, he has to pick between two women -- perhaps the toughest decision of all. Peyton (Clare Forlani) -- Mac's former lover -- returns for the first time since dumping him and moving to London. But her return comes just as Mac has settled into a new relationship with emergency room doctor Aubrey Hunter (Mädchen Amick).

Will Mac be able to make the right call? Is choosing between two different women even tougher than solving crimes?