📖 N or M? (+ CD-ROM)

"N or M Song Susie"... The last words of a murdered government agent - and a cryptic message left to Tommy and Tuppence Beresford to decipher. Common sense suggests they begin with the Sans Souci Hotel. But once inside the seaside resort, the Beresfords are greeted with hostile guests and a mysterious hotelier working incognito, baffled by ransacked rooms, and haunted by a report that a young girl has gone missing. When Tommy himself vanishes, Tuppence has reason to fear that checking out of the Sans Souci comes at a perilous price...