On this episode of Castle:

- A stripped cab is found near a warehouse belonging to Amir Alhabi, a Syrian immigrant. The cab is owned by brothers Amir and Jamal. An annotation was found in his phone, C4121652. For extra money the cab was rented to other drivers, including Kevin McCann who had a fight with Amir recently.

- CSU finds mini cameras in the cab with the hard drive ripped out. The cab’s GPS leads detectives to a Fariq Yusef, who wanted Amir to come home and be part of a weapons program.

- The annotation takes Castle and Beckett to a storage unit where explosives had been housed with high levels of radiation. Homeland Security sends Mark Fallon to work the case. $10K had been deposited in Amir’s account after being wired from six different banks.

- Video footage of the storage unit shows Jamal wheeling out a crate before detectives got there. The bomb and him have been missing for several hours. Castle meets with Fariq and gets Beckett and himself kicked off the case by Fallon.

- GPS shows McCann had also driven to the warehouse recently. Castle and Beckett go and find Jamal’s truck with the bomb and C4 inside. Someone starts shooting at them and they back behind a door where Jamal is found dead.

- Beckett’s boyfriend is leaving for a Doctors without Borders mission, causing her to confess to Castle she just wants someone who will be there for her.