Nobody leaves a lamp burning.

Helen Price transcribes medical dictation seven hours a night. From her desk in Greenpoint she can see one lit window across a twenty-foot courtyard ? and for eleven nights she has watched a man walk into that room and kill a woman.

She has called 911 four times. A unit has been inside twice. The apartment has been vacant since May. There is no tenant. There is no woman. There is no body.

Dr. Elias Mercer is hired to write two lines explaining why she can't be believed, and he is the right man for the job. Fourteen years ago he wrote more than he could prove, and it cost him everything. He has been careful ever since.

Then he reads her notes.

Her description of what she sees changes every single time ? the clothing, the hair, the distances. Her description of what the man does never changes at all. Not one word, across sixteen days.

People who imagine things vary. People who lie guard their details. This woman does neither.

Something is happening in that empty room at the same minute every night, with the lamp on and the curtain drawn exactly halfway. Every part of it is unnecessary. Every part of it was chosen.

And whoever is doing it needed a witness ? one nobody would believe.

He has eleven days to work out why.

The Woman Upstairs is the first novel in The Elias Mercer Files.