Criminal Minds by Karen Neal/ABC Criminal Minds by Karen Neal/ABC

In tonight's Criminal Minds finale (9 pm/ET, CBS), the BAU team heads to New York City on the trail of a Son of Sam like serial killer - or is there more than one?

That's not the only question: J.J. ( A.J. Cook) makes a fateful pregnancy decision, Hotch ( Thomas Gibson) discovers he has an admirer and Morgan ( Shemar Moore) ponders leaving to run the New York office.

And in the explosive cliff-hanger, "one of our team is going to be severely injured, and [viewers will] have to wait all summer to find out who it was," says exec producer Ed Bernero. "If you care about these people, you cannot miss the last 30 seconds."