Wow. Leave for a week and Rookie Blue drops some pretty big bombshells. In "Poison Pill," Andy found out that Marlo was bipolar and that Sam doesn't know - and Chris apparently said goodbye to 15 Division. How do you follow that up?

Frank calls a meeting to tell everyone that "Diaz is gone and he won't be coming back," which wounds the entire team (and all of us Travis Milne fans, naturally). His speech amounts to "Get over it" before he dismisses the ensemble. Gail has desk duty, which means she has to talk to a man about his missing daughter, Grace. Unfortunately, Grace hasn't yet been missing long enough to open a case, but Gail senses bad things.

Upstairs, Traci hates that Sam changed the filing system, and gets a little tetchy with him before he introduces Gail's brother Steve (Adam MacDonald), a Guns and Gangs detective she's got to work with. And on the street, Chloe rants at Marlo - the absolutely wrong person - about being mistaken for bipolar.

Elsewhere, Nick and Andy investigate a dispute over a stolen cab - which leads them to security camera footage of an abduction. Andy is shocked when she finds out the cab was registered to Ross Perik, the man who abducted Gail and killed our beloved Detective Jerry Barber. (Hands up, who's still upset over that one? Yep, so are we.)

Time to bring in someone particularly awesome: Luke Callaghan (Eric Johnson). Say what you will about how he botched his relationship with Andy - which might be why Sam doesn't look thrilled to see him - but Luke knows his police work and there's something comforting about having him around. He points out to the assembled members of 15 Division that Grace matches the existing victim profile, and if this is a copycat following after Perik, then they've got twelve hours to find her.

While Grace's dad understandably flips out on Gail and Nick, Traci and Steve start their own investigation into a gun trafficker which is revealed to just be a huge distraction to keep Traci off the copycat case, and Chris Owens (who played Jeffrey Spender on The X-Files years ago) pops up as a concerned member of the neighborhood.

Meanwhile, sad piano plays while Sam and Andy find themselves with a few minutes to have an awkward not-conversation about working together. They find out who bought the cab after Ross had it, and formulate a reason to break into his apartment. Sam hauls the guy in for interrogation, during which he says that he doesn't know who he sold the cab to. "He's garbage," Sam deduces, "but not who we're looking for."

Luke tells Frank that forensics found traces of the same chemicals Perik used on his victims in the back of the cab, and since that information wasn't released to the public, that's pretty damn incriminating. He wants a sit-down with the killer. Sam does not approve of this idea, especially when Frank says the only person Perik will talk to is Gail.