Eric (Eric Morecambe), in his London coffee bar, is happily serving black coffee to a sinister-looking man (Tutte Lemkow) when the man tries to persuade him to remember a tune. Unfortunately, Eric is Tone deafness. Ernie Sage (Ernie Wise) enters the coffee bar and Eric tries to get him to identify the tune, without much success. Eventually, Sage realises that this could be something to do with a forthcoming visit by a Russian trade delegation and an assassination attempt by an organisation known as "SCHLECHT" to sabotage this mission.