A teenager is nearly attacked with a knife, but someone attacks the would-be attacker using a taser.

Laura moves into her new house with Mark's help. Mark accidentally says he loves her, but Garza calls her into the office before she can reply

Mark is left arranging furniture in the house.

Garza introduces the team to a curious case of severed limbs. The team is tasked with finding the killer before he strikes again.

Elena watches as Antoinette inspects one of the limbs, and they discover something. All the victims were siblings.

Simone interviews the wife of one of the victims, and she reveals that he is a casual criminal.

While chasing down leads, Simone and Carter learn that the murdered man was caught stealing and that he and his siblings were biologically fathered by a serial killer who had been incarcerated by now.

They visit the fertility clinic responsible and interview the doctor. He revealed that their servers were hacked and records deleted, but they had physical files.

Simone runs into Cutty in the hospital.

The FBI offers protective detail to all the remaining siblings.

Simone, Carter, and Nolan visit one of them and informs her of the killings.

Laura calls another who has been revealed to be a serial killer. He is right where Simone and Carter are, and they see him, but he escapes.

Brendon and Antoinette join Laura and Mark at her new house and Mark and Laura fight passively. Laura decides to buy something, but the killer kidnaps her before she can get into her car.

After a while, the remaining group members realize something is amiss and discover the kidnapping.

The killer takes Laura into his den and talks to her. She manages to free herself, but before she can escape, he finds her, and they fight.

The team figures out where she might be held, and Mark and Brendon find her in time. The killer commits suicide.

Mark and Laura return home, and Laura tells him she loves him.

Simone visits Cutty in the hospital and learns he has an ear infection.

Elena expresses interest in becoming a forensic scientist.