In the time they've known each other, Sally, Al and Mike have shared - well, almost everything. Sally and Al have been married for seven years, but now their relationship is hanging by a thread. Sally and Mike have been best friends since university. Mike and Al have been friends for many years. Yet with Al poised to become Mike's boss, their relationship is coming under threat. And now there's Mike and Faye. They haven't been together long, but Mike's pretty sure that this time it's the real deal. As the three old friends sit on a train heading towards Brighton to meet Faye, little do they know that after this weekend, the four of them will have shared...everything. They all know they have made a mistake. But they could never have imagined the consequences.