Ex-naval lieutenant Bobby Jones and his childhood playmate Lady Frances (Frankie) Derwent join forces to unlock the mystery of a dying man’s last words: "Why didn’t they ask Evans?".
Frankie Derwent and Bobby Jones plunge deeper into a thickening conspiracy, crashing a Trojan Horse into a brick wall to infiltrate the house of their principal suspect.
Frankie and Bobby’s suspicions shift to the menacing figure of Dr James Nicholson, bringing the pair one step closer to answering the cryptic question: Why didn’t they ask Evans?
Risking life and limb for each other and for the infernal puzzle, Frankie and Bobby finally run the question to earth and discover exactly why ‘they’ didn’t ask Evans.