When twins Holly and Dylan Meredith go missing, Officer Lisa Armstrong realises her connection to the family might be more than just professional.

With the Meredith family reeling from Dylan's death and Sean's arrest, Lisa is charged with finding his alibi and makes a game-changing discovery.

Sean's revelations lead the team to suspect Nick might have vital information about Holly and Dylan.

With Nick seriously injured in the hospital, Lisa furiously seeks out Sean, while Med feels increasingly sidelined.

A confession to Lisa shines a new light on Dylan's killer.

Despite what Holly tells the police that she killed her brother, they believe there's is more to the truth than she has told them.