His gaze was fixed intently on a Margarita glass, sitting on a table, unoccupied. Nancy had gone to the toilet, for about the tenth time this evening, leaving her glass unattended.

So far, only two attempts had been made to spike her drink. Both attempts had ended badly.

The glass was sitiing on a coaster that Roland had designed ( The DrinkSentry). It was a pressure-sensitive pad about the size and shape of a normal coaster but considerably thicker.

The series of high voltage capacitors built into it were designed to discharge if anything touched the glass or hovered over it for too long, unless the remote blocking device was in the vicinity. Nancy was wearing the RBD on a necklace, so the coaster was armed and ready.

The guy who had hit on her earlier slipped past the table, his hand dipping towards the glass... Another victim! He leapt suddenly backwards, shaking his hand violently and cursing. 50,000 volts into the fingertips, even at low amperage, will do that to you.

Roland waited for Nancy to return, before heading home for the night. She was a good sport, he realised.