1. Ginny has died under suspicious circumstances and Harry is the prime suspect. Severus is investigating the crime. Severus can't decide if he wants to save or convict Harry of the crime.
2. Suffering from exhaustion after the Final Battle, Harry ends up in an isolation room in the infirmary, mostly to keep everyone away. Due to limited space, Severus is placed in the same room. What do two old enemies talk about?
3. Tired of all the attention after defeating Voldemort, Harry withdraws to the house on Grimmauld Place. He's changed the wards to keep everyone out but doesn't know Severus built his own 'back door' into the house years ago to use as a disaster escape if he needed. Harry's friends convince Severus to go after him.