The Vow And Its Consequences

Dudley Dursley demands to go to the fair, which happens to be in Cokeworth, where Petunia and Lily grew up. It's also the place of residence where our favourite dungeon bat resides. They go during the summer holidays...needless to say the vow Severus Snape swore comes into play with long lasting ramifications. For who? Albus Dumbledore? Lord Voldemort? Severus Snape? Well everyone is about to find out.