The Deep Six Affair (S04E14)

In London, U.N.C.L.E. agent Brian Morton (Peter Bromilow) is excitedly preparing for his wedding, much to Waverly's chagrin. Solo and Illya step in to assist Morton with an important task: preventing THRUSH agent Commander Kroler (Alfred Ryder) from acquiring the blueprints for a new advanced submarine. Waverly attempts to convince Laura Adams (Diana Van Der Vlis), Morton's fiancée, to rethink the marriage, but she remains steadfast. Things take a dire turn when Kroler kidnaps both Morton and Laura, threatening her life unless Morton retrieves the submarine for him.