Leo's (Jacky Ido) son comes into town with his wife, but the trip takes a turn for the worse. Cat (Chyler Leigh) gets caught up in an investigation and has to prove her innocence before she can help Leo save his family. The episode ends in an unsightly disaster that prevents Cat from finding answers.

A motorcycle messenger making a heroin delivery is shot by another motorcyclisty; an amateur basketball tournament leads to a startling discovery.

What Cat arrests a member of Jungle K's gang, he gets a hold of a gun and shoots up the precinct, leaving two cops dead.

When a maid from El Salvador is shot in Brooklyn, Cat, Leo and Frankie discover she is actually a former cop from Venezuela who is in town seeking revenge.

When Cat and Leo discover a man who was exposed to a weaponized toxin in a dumpster, the NYPD goes into high alert.

Evidence in the deaths of three different men points to one murderer, a black widow; Leo goes under cover to catch the killer

The wife of the Park Slope stalker is found dead, bringing Cat's buried emotions to the forefront; a shocking discovery is made

A female inmate escapes during an attack on a transport van who turns out to be the witness to the murder of Cat's father.

A foster mother is murdered, prompting an investigation by Cat and Leo. Before long, Cat is surprised by the bond she forms with one of the foster children. The case turns personal for Leo, who misses his own son in France. Meanwhile, Cat asks to open a case into a mafia family.

Though Cat may not want to admit it, she and Leo are proving to be a great team. His insight has helped her close two cases. But this week, it's Leo who ends up needing Cat's help when a dear friend is murdered.

The infamous, hell-raising son of a well-known handbag designer goes missing.

A detective who was demoted to foot duty makes a deal with a cabdriver with a past.