An alarm.

Frank awoke in darkness, roused by a soft but insistent beeping that he recognised as a burglar alarm. Almost instantly alert, he got a pistol out of the night table drawer and stepped into the next room, which held his security system, looking at the perimeter display.

He had it installed before he moved in, on the same theory that had him hide guns in almost every room of the house. If his old enemies ever found him, he wanted to give them all the fight they could handle.

The display showed attempts at two windows, and as he watched, a third showed an indicator. The system showed none had actually been breached, but someone was clearly trying windows.

The question was who.

And why?