Ulla, a teacher from Roskilde, has celebrated her 30th birthday with a big party among friends and relatives. On her way home from the party she disappears without a trace. Her husband calls the police and Unit One is summoned. Evidence indicates that a crime has taken place, and Ulla's children also face danger. Ingrid is in an awful state following Søren's death and has incarcerated herself. Gaby and Johnny try to help, but in vain. However, IP has his own way of tackling Ingrid. Fischer receives a tempting offer from Ulf.

Fischer and La Cour have taken a holiday on the North Sea with Fischer's family. Their holiday is soon ruined when the local force receives an anonymous tip-off that a homicide has been committed in the neighborhood. The murderer is at large and could strike again at any time. Ulf is summoned when Fischer loses control while detaining a subject.