He needs someone to show him the ropes of being grown up and mature. She's just bored. Also, she needs help with Sixth Year Transfiguration. Put them together and what do you get? A fake-dating couple that takes Hogwarts by storm. [Eventual James/OC; starts Sixth Year; AUish; Romance/Friendship/Humour]

When bullied by the other Slytherins and rejected by his brother, Regulus wishes Sirius could understand his problems and feel what it was like to be him. However, his wish is granted in an unexpected way. He and Sirius have swapped bodies and now must spend the day as each other: Regulus with the Marauders, and Sirius with Regulus's future-Death-Eater dorm mates.