Four Estonians who have lived in Sweden since World War II are recruited by the intelligence service and trained as spies. Their mission is to infiltrate their homeland, spy on military installations and recruit sympathisers in the fight against the Soviet regime. But one of the agents is injured as they land their craft on the Baltic coast, leaving behind traces of their arrival, and the Estonian counter-intelligence forces take action … The opening credits state that the film is “based on true events”. And indeed, between 1949 and 1955, West German E-boat crews led by commander Hans-Helmut Klose ran missions for Britain’s MI6 intelligence service to land on the coasts of Latvia and Estonia. The film based on that premise is a straightforward, realistic spy thriller; designed to motivate vigilance in home audiences, it also no doubt entertained them splendidly.