Once he'd gotten over the shock of seeing another of Brennan's team having arrived in LA, Booth discovered that he was feeling no small degree of apprehension about going to retrieve Zack. He'd started caring about the kid just in time for him to betray them all because of logic. But the past needed to be the past for the moment until they'd gotten him and brought him back.
With Bones in tow, Booth set off for the cafe at the address Zack had given them. "All we need is Hodgins and Cam and we'll have the full team. Maybe you could open up your own Jeffersonian right here in freaky LA," he teased her, giving her arm a small poke.
As they found the place, Booth pulled open the door and stepped inside, taking off his sunglasses and squinting as his eyes adjusted to the light. "Zack?"