The team search for a nurses' aide who who disappeared from a rural road while changing a flat tire, only to discover that she is actually a fugitive wanted for the bombing of an abortion clinic.

When a homeless woman disappears from a shelter, the team is forced to re-examine the case of twin brothers Greg and Rick Knowles. Five months earlier (Doppelganger), Greg Knowles had confessed to a series of brutal murders, but the team was always convinced that it was Rick who had actually performed the killings. When Greg is released from jail and exonerated of the crimes, the team has to work against the clock to prove that Rick is the guilty party and to save one twin from the other.

Cindy Peterson, a mother who had become a stripper to support her family, goes missing after work one night, and Jack sends Elena in undercover at the strip club to learn what she can. Danny moves in to keep an eye on her after someone catches on to her spying, while Vivian discovers that Jim Peterson hasn't been completely honest with them. Jack faces censure from Olczyk over his relationship with Ann, and is angry with Ann after she admits to him that she thinks he let their relationship cloud his judgment in the Davis investigation.

A newly elected senator goes missing and Jack immediately turns his attention towards her husband.

Sam's darkest secrets are revealed when her sister goes missing she decides to search for her without the team's help.

While struggling to deal with the aftermath of Jack's accident, the team searches to find a teen heart transplant recipient, believing her disappearance might be connected to her donor. Samantha talks to Brian.

Five people with an odd connection go missing from a coffee shop, and the team determines what the connection had to do with their disappearance. Meanwhile, Samantha gets ready for the birth of her child.

The team finds a secret to a bank manager's past after she vanishes, which may just hold a clue to her disappearance. Meanwhile, Jack is named head of the department once again.