A city bus explodes.

Jubal's son Tyler has just transferred to a new school.

Jubal tells Tiffany her annual review is coming up and their recommendation is that she become more assertive.

Then their phones go off.

Ten people were killed in the bus crash.

Maggie offers up Ansar Allah as possibly the responsible terrorist group.

The team checks out the crime scene.

A witness saw a man drop off a backpack and then walk away, later climbing into a cab.

The team tracks the suspect to where the cab dropped him off.

He runs and takes a man hostage until Scola is able to shoot him from behind, unfortunately killing him.

Searching the suspect's home, OA finds a banner for Al-Shabaab, a terror group based in Somalia.

Isobel interrogates the suspect Balin's widow, who claims she wasn't involved in his terrorist activities.

She said he changed after family members were killed in the bombing of a community center in Somalia by U.S. allies.

He had been hanging out in Harlem with Somali activists led by a man called Hakim.

Tiffany suggests going undercover at the restaurant and taking Hobbs since Scola would stand out in Harlem.

Hakim makes Hobbs and shoots and kills him.

Isobel gives a shaken Tiffany a chance to sit out the investigation, but Tiff refuses.

Ian pings Hakim's phone, and the team goes there to search. He ditched the phone, and a kid found it.

Surveillance footage from a camera Tiffany spotted shows Hakim getting into a car driven by a waitress from the Somali restaurant.

Elise finds the car after reactivating its GPS.

They find the waitress but not Hakim. Tiffany gets overaggressive, and Maggie warns her to pull back.

Elise locates Hakim going into the subway.

Ian finds photos on Hakim's phone of a cemetery near the World Trade Center.

Maggie and OA spot Hakim who sets down the backpack he's carrying.

He runs into a fashion show with Maggie and Tiffany giving chase. He takes a hostage.

Tiffany chases Hakim but gets clipped by a panel van and loses him.

Jubal informs Tiffany that she made the right call in pushing Hobbs to check out her hunch.

The unit drinks to Hobbs who gave OA his nickname.