I've been looking for this for ages: it's a story where John never goes to Atlantis, he gets discharged after Afghanistan with PTSD. He ends up living in Rodney's house, which Rodney has rented out whilst he's in Atlantis. He finds Rodney's diary and reads it, and he ends up geting obsessed. He also rescues Rodney's cat from the shelter. Then Rodney shows up. Does anyone know where I can find this?