Late Check-Out: No Light May ShowOne hour until the aircraft leaves

Half a page, brown at the edges, smelling of smoke: the bottom half survived. It is ten o'clock, and the stop-word is not written on it in any form London would recognise.

Hour Five: the word for London

A black wartime telephone on a small table in the corner of a dark hall, a hooded lamp bent low over it, an open ledger on the shelf beneath, and across the floor the oak stair with its carved newel post. Nobody there.

What is left of tonight's page is the bottom half, brown at the edges and smelling of smoke. The school never writes a stop-word plainly. Mrs Reeve, who sets them, writes each one as a set of clues, so that a page picked up in the wrong hands is only a puzzle. She has spent the summer reading her guest's books, and it shows:

OP TEAL/ROOK
STOP-WORD
1 the country of the
  little Belgian's Nile
  cruise
2 the old lady of St
  Mary Mead
3 the little Belgian's
  own country
4 the county of Styles
5 Mr Ackroyd's first
  name

Mrs Christie reads it over your shoulder and laughs out loud for the first time all evening. She says she has never been so flattered, or so badly paraphrased, and that she will not help: a woman cannot be expected to solve her own books. London is on the line, waiting.

A ruled book lying open on a dark table, the edges of its pages scorched brown, a candle burning beside it and a black telephone at the edge of the light. Nobody in sight.

Give London tonight's stop-word.

To two minutes to midnight.