Love is in the air in Albuquerque, as Mary is forced to tend to a lovesick witness pining for his childhood sweetheart.
When Jimmy Hart finds out the au pair company he's been working for is actually a front for a human trafficking ring, he's appalled-and ready to testify, no matter the personal cost. But when he learns that prosecutors are trying to build a case against Winnie, his lifelong best friend and crush, Jimmy stonewalls. He'd rather go down himself than hang her out to dry.
Marshall's own protective instincts (and feelings for a special female friend) land him in hot water of his own, when a training exercise in which Mary appears to be imperiled inspires an uncharacteristic outburst of aggression from Marshall. He soon finds himself benched and forced into visits with Dr. Finkel, leaving his partner to tend to Jimmy and Winnie on her own. Despite her resistance to the assignment, Mary soon finds herself square in the middle of their love story. And as it turns out she's actually a whiz at bringing people together-kind of like Cupid, only angrier. And with a gun.