Season 2 Episode 12
"The Mystery of the Unwelcome Houseguest"
Laura races against the clock to solve a murder - and save her own life. Jerry O'Connell and Stockard Channing guest star.
An unhinged Jon Dunham sneaks into Laura's house and holds her hostage at gunpoint. Jon believes Laura framed him and wants her to make a video confession. Jon is irrational and clearly off the wagon. He brings out a bomb with a timer set to 100 minutes, so Laura agrees to give a (false) confession. After an attempt to escape fails, Laura realizes Jon means to kill her, so she refuses to do the confession, telling Jon she didn't kill his father. When Jon convinces her that he didn't do it either, Laura realizes there is still a case to solve.
Meanwhile at the precinct, with no remains found at the blast site, the team realizes Jon is still alive. Jake becomes increasingly concerned about Laura's absence, and when the boys' nanny tells him Laura is sick from bad clams, Jake knows this is a code. Laura is in trouble. He and Billy head to Laura's house, where they arrive just as Laura talks Jon down. When Jon puts down his gun, Jake bursts in. In rapid succession, Jon pulls the 120-second trigger on the bomb, Jake and Billy wrestle Jon to the ground, and Laura throws the bomb into the washing machine before it goes off - causing an explosion that ruins the washer but leaves everyone unharmed.
With Jon in custody, Laura still believes he didn't kill his father. During questioning, Jon makes a comment about the corrupt police on the Vineyard, and Laura makes the connection. His assistant, Ellen, had a Vineyard mug. During their hostage standoff, Jon admitted to killing a family in a drunk-driving accident years ago. Max does some sleuthing and reveals that the accident happened on the Vineyard and there was a surviving daughter: Ellen. Laura and the team use the power of suggestion to trick Ellen into planting the murder weapon at the blast site, where they catch her red-handed.
Later at the bar, Meredith mentions Tony to Laura, and Laura realizes she didn't think about him at all during her ordeal. She says the day made her realize what's important... and looks at Jake.