As the legendary carriages of The British Pullman journeyed back to the Festival of Britain, ten suspects moved fluidly among the guests, unravelling a 1951 thriller in real time. Each detail was a clue in itself - tailored costumes carrying distinctive character scents, a swan brooch, paisley motifs echoing the carriage's own aesthetic, a bespoke Luxury Locomotives Magazine laced with hidden puzzles and an illustrated map. Guests could interrogate suspects between courses, or simply sip champagne and let the drama find them.

The train had a timetable. The mystery did not.