The leaking of secrets at Carmadoc Research Establishment throws suspicion on to Steed, who must suffer the torment of house arrest while Tara goes in with a new partner.

The spectacular theft of 3,000 top-secret FF70 rifles from a Government establishment brings Steed and Tara. Steed meets an old 'friend' and is invited to an auction. Tara has other reasons for being there.