Annika assembles her team to solve murders in the waters around Glasgow, and their first case looks a lot like a whale hunt gone wrong.

Annika's teenage daughter, Morgan, gets mixed up with suspects in a revenge slaying, and Norse mythology comes to life as Annika's team closes in.

Annika sees one of playwright Ibsen's plots play out in a homicide, and she takes more than a parental interest in Morgan's therapist, Jake.

An author who ruins lives watches the same happen to her own; Blair finds a friend for Morgan; Annika and Jake go to a museum exhibit.

An early morning call out to a party boat on the Clyde reveals the body of Paul Gilbride, a Glasgow businessman killed during his anniversary party, and thrown in the river from the boat. The kind of guy everybody loved, the team delve deep into his life to find motive for this brutal murder. Annika (Nicola Walker) looks to the Greek stories of revenge and sacrifice to help her solve this crime, especially when the method of his murder is revealed.Annika admits to Morgan (Silvie Furneaux) that she's been seeing Jake (Paul McGann), and the three have dinner together. However, when Annika is called away on a case, a conversation with Morgan makes Jake question if this is the right time for them to date.

Michael's brother becomes the prime suspect in his ex's murder; Annika goes for what looks like a one-way ride; a secret about Michael comes out.