The first time they had sex was after a night out with the team. Long week, tough case, hardly any sleep, and then the darkness of the club, loud music, dancing and a drink or two. They ended up at Sara's place, in Sara's bed. Naked, sweaty and utterly spent. Hours later, when they woke up, they both felt awkward about it. But not awkward enough to pretend it never happened. Not awkward enough to pretend it wouldn't happen again. It did. A pattern emerged. Catherine turned up at Sara's, they had sex and then slept for a while, and when they woke up, Catherine left. There was never any talk of it being anything more than sex. Until one day, Catherine asked if she could leave a spare toothbrush at Sara's. That changed everything.