Moving through the vaulted lobby, past the gift shop to her left and the pool to her right, she took a quick turn down the corridor leading to the hotel’s gym. It wasn’t crowded at this time of the night, but nor did she have it to herself. Two women were chatting while using the elliptical trainers, barely raising a sweat. In Caitlin’s opinion, if you had the breath to flap your gums you weren’t training hard enough. A couple of guys were pounding through the miles on the treadmills. She’d have picked them for military because of their haircuts and physique even if they hadn’t been wearing PT shorts with the emblem of the USAF printed on them. She was glad her own gym clothing was civilian. She didn’t fancy having to play the Murdoch role with those two. The other users down here she lumped into two broad groups: government and business travellers. All of them huffing and puffing in a desultory fashion, grinding through the same exercises they’d probably been doing for the past ten years. No doubt they’d train at half intensity for about a third of the time they actually needed to before rewarding themselves with a pig-out at the hotel buffet.

Still frowning and feeling bleak, Caitlin started her routine under the black cloud that had settled in over her. She began with a quarter-hour of dynamic stretching before taking the last of the cross trainers and blocking out the inane chatter of the women beside her. It would’ve been easier if she’d had a music player and some headphones, but she didn’t like the way it was possible to zone out when wearing those things. Zoning out was the enemy of situational awareness.

After half an hour she was sufficiently limber to attack the weight stations, which she did with a vengeance for the next hour and a half, mixing up weight training with bursts of high-intensity cardio intervals. One of the air force types did his best to attract her attention, but she froze him out. She wished she could’ve worn her wedding ring to warn these creeps off, but for a field agent, that telltale golden band screamed: Weakness. A pressure point. A chink in the armour.

Isolation was her armour and Caitlin’s was restored by the time she’d finished and was heading back up in the lift, just after ten. Again, it would’ve been nice to have indulged in something as unremarkable as a hot tub, but she had no desire to have to shut down anybody foolish enough to talk to her. And she still had hours of work to get through before she could even think about sleep.