You've only got one shot

Annabeth and Percy. The two were best friends, inseparable since they were 12. Now 19, they share a flat with their other best friend Grover. They'd been out of the demi-god limelight for a while but of course, it had to end soon, right? The two decide to tour around the UK, all the villains and creatures they'd met along the way come to haunt them. What will happen? Who knows...