If this ends up being the last episode ever, it's actually a perfect one. So I'd be OK with that. I like the open-ended-ness, which suits a mind-eff time-travel series.
Sarah's stuck at the jail the whole time. She gets word to John that he's supposed to leave her and move on. Ten bucks says that Mama's Boy can't leave well enough alone.
Shirley Manson Terminator wants to meet with John. Ellison finds John and Cameron, but John won't agree to meet with Shirley. In that case, Ellison asks Cameron a question from Shirley: "Will you join us?" Cameron claims to not know what that means.
Cameron and John show up to the jail to spring Sarah. John Henry watches the whole thing on the video monitors and helps disarm the security system. This means all of the prisoners break out and their escape is even easier in the ensuing chaos.
A Terminator arrives to kill Shirley, but of course she's a liquid metal model so she deflects the bullets... and electrocutes the Terminator. John Henry works to determine who sent the Terminator.
The Connors go to meet with Shirley Manson Terminator. Shirley tells them they have a common enemy - Sky Net - that she's been working to destroy. Then a flying Terminator comes crashing in the window and Shirley liquidizes herself into a metal shield to save them.
Meanwhile, Cameron goes to meet with John Henry. They're all "I know you." "I know you." "Will you join us?" When the Gang gets downstairs they find Cameron's "dead" and her chip is missing. She gave it to John Henry (to literally join them - which I totally called)... and they determine that he has time traveled. Shirley asks Ellison to pick her daughter up from gymnastics (LOL!) and then Shirley and John time-jump to find him. Sarah stays behind.
In the future, Derek (HI DAVID SILVER!) finds John - and he's never heard the name John Connor before. Also, John's Daddy is there with Cameron (I'm thinking it's the human version of Cameron). Well aren't we a big happy family now?
At the very end, we see someone transporting themselves into the future and Sarah's voice saying, "I love you too."
BONUS: The ad for Terminator: Salvation. OH HOLY NIGHT I can't wait for that movie. And the music gets me cised, as always.