Callen and the OSP team enter a warehouse full of information on various agents. Information that explodes almost immediately when Kensi tries to hack the computer.
Callen fears his past is lost forever - a huge folder bearing his name went up in flames - but he's got bigger fish to fry. Namely an Iranian terrorist looking to rise to power.
The linchpin, interestingly, is a woman masquerading as Callen's sister. She's not actually his sister, but knew her in an orphanage years ago, and took her identity when she died.
We learn that Callen's sister may be dead, but someone has been watching him the whole time ... his mother or his father is still out there.