Old Vows (джен)

Tom Riddle is back, resurrected by dark magic, and the wizarding world is on the cusp of a new war. Albus Dumbledore tries to deal with the aftermath of the sudden reappearance, watching the wizarding world shift around him and preparing himself for coming battles. But he isn't the only one who is faced with new and old duties, and Severus has not yet returned from his first visit to the newly risen Dark Lord...