Codename: Calypso - a young woman is murdered and the team investigates a cocaine distribution ring out of South America. Hallgrim rents a house from a beautiful woman.
Hallgrim and team work to discover the identity of "Groom" who is the main suspect of the child's murder. When it is discovered that his wife is attached to a child rescue program more questions arise about the child pornography ring.
Codename: Minos - Thea returns and makes plans for a foreign minister's visit. The team works on convincing a war criminal to testify and in the process one of the team is seriously injured.
Codename Minos (part 2) - while the team deals with their loss, the pursuit of Bosch continues. Hallgrim learns of new jamming technology which could have devastating impacts. Thea and the Serbian Interior Minister are abducted.
Hallgrim receives a message from beyond. Before leaving for Iceland, Hallgrim finds that Bosco has escaped. Michael is charged with homicide and must leave the team.
Codename: Ithaca (part 2) - Hallgrim is finally in Iceland and the search for Bosco continues, with the CIA joining in. In the series finale, many issues are resolved.