Caitlin "Cat" Sullivan is an NYPD detective working in Brooklyn. After her driving privileges are suspended, she relies on Leo Romba, a highly skilled Brooklyn cab driver from France. Leo becomes Cat's driver and a consultant on her cases. While solving crimes with Leo, Cat is also running her own unauthorized investigation into the death of her father, an NYPD detective thought to have been executed by the Capella crime family. In doing so, she clashes with her boss, Captain Baker, and her ex-husband Gregg, who has picked up the case for the FBI.

Dan Chase absconded from the CIA decades ago and now lives off the grid. When an assassin arrives and tries to take Chase out, the old operative learns that to ensure his future he now must reconcile his past.

In a sun-soaked Hawaiian town with a mysterious past, a group of friends is left with a dark secret after a tragic accident. One year later, a member of the group receives a threatening message, and the friends now know that someone intends to make them pay for last summer.