ABC 20/20

On her last day of work, homicide detective Sarah Linden is drawn into a new case about the disappearance of a teenage girl: Rosie Larsen. Mitch and Stan Larsen frantically try to track down their daughter when they learn she did not show up at school.

Linden and Holder visit Rosie's high school to question classmates and teachers about where she may have gone after the dance; Richmond and his staff go into spin mode over the fact that the victim was found in a car linked to his campaign.

Police try to determine the connection between the teen girl's murder and the grisly crime scene at "The Cage" in the basement of the high school.

Sarah and Holder pressure Rosie’s former boyfriend, Jasper for answers and interview a new suspect; an emotionally vulnerable Stan and Mitch plan their daughter’s funeral; Rosie’s best friend, Sterling, reveals some surprising truths about Rosie’s life.

One of Rosie's teachers provides Sarah and Holder with crucial new evidence. Meanwhile, the Richmond campaign comes up with an anticrime TV spot; and Stan steps up his search for Rosie's killer and enlists Belko's help.

Sarah and Holder question a suspect’s family and neighbors. Tension mounts between Richmond and his campaign advisor, Gwen, as his team prepares for an important debate with the Mayor.

Stan offers Bennet a ride home from Rosie’s funeral, knowing he’s the main suspect in his daughter’s murder. He pulls over on an empty stretch of road and Bennet knows something is amiss.

Sarah and Holder uncover evidence; Mitch endangers the boys; Richmond tries to get back in the race.

The police make a shocking realization; the Larsens are fed up with the police.

The police regroup; Richmond advances in the polls; Mitch is left to keep the family afloat.

Sarah and Holder set out on a search for Jack.

The police connect Rosie to a suspicious website. The waterfront project is halted. Stan faces his demons while Mitch learns secrets she never knew about Rosie.

The identification of the mysterious Orpheus provides a vital connection to the case; Mitch and Stan reflect on the past while contemplating their family's future.