She pulls out her phone, dials again, says, "Number thirty-four," then puts it away. Then she opens her go-bag and pulls out a pair of goggles. She pulls them on and flicks a switch. Then she stalks around the side of the house.

There is a bad smell from the drains out back, and the lawn is un-mown. The hedge has not been trimmed: it looms over the over-long grass like the dark and wild beard of the god of neglect. The windows of the house are dark, and not merely because no lights shine within. It's strangely difficult to see anything inside. Mo stares at the flagstoned patio beneath the French doors through her goggles. They are goggles of good and evil, part of the regular working equipment of the combat epistemologist, and their merciless contrast reveals the stains of an uneasy conscience mixed with the cement that binds the stones: it's an upmarket Cromwell Street scene, she realizes, her stomach churning. The police forensic teams will be busy here later in the week, as the tabloid reporters buzz round their heads like bluebottles attracted to the rotting cadavers beneath their feet.

Mo moves farther around the house. A sense of foreboding gathers like static beneath the anvil cloud of a thunderstorm. Her heart is beating overly fast and her palms are clammy. She is certain that Bob's phone is here, and where goes the phone goes the Bob. But this is not a good place. Suddenly she is acutely aware that she is on her own, the nearest backup ten minutes away.

Well, then.

There is a quiet click as she unfastens the latches of her instrument case. Moments later the bow is in her hand, the chinrest clamped between her jaw and shoulder. The case dangles before her chest, two compact speakers exposed. There's a sticker on the back of the instrument. It reads: THIS MACHINE KILLS DEMONS.

Mo walks towards the glass doors, on the indistinct shadows behind them, and touches her bow to the strings of the pallid instrument. There is a sound like a ghost's dying wail as the strings begin to vibrate, blurring and glowing as they slice the air to shreds. "Open," she says quietly, and as she sounds a chord the glass panes shatter simultaneously and the door frame warps towards her. She advances into the suburban dining room, playing raw and dissonant notes of silence to confront the horrors within.

THE BMW IS HALF A MILE AWAY WHEN PANIN LEANS FORWARD and taps his driver on the shoulder.

"Sir?" The driver glances at Panin's reflection in his mirror.

A blank business card appears between Panin's fingertips, twin to one Panin passed to an unwitting contact a couple of days ago. "Track this," he says.

"Yes, sir." The driver reaches back and takes the card, then places it on the dashboard in front of him. It glows faintly in the darkened interior of the car.