The Secret Singer

It's been a year since Nico and Will's trip to Tartarus and people seem to be moving on with their lives. Annabeth and Percy are both studying at New Rome University, Hazel and Frank are becoming more comfortable in their roles as Praetors, Grover is leading Satyrs in re-planting some nature spaces, and Reyna and Thalia have been with the hunters for a while and haven't been seen by either camp in six months. Piper and Leo haven't made contact but from what Apollo told them it seems they are setting in their new lives. Everyone has moved past their demigod lives more or less. Everyone except, it seems, Nico and Will.
After their expedition to Tartarus, Will began to get nightmares. He and Nico now share the roles of comforter and comforted and they help each other discover and control their new found gifts. All seemed well for them until Nico got a job in a city that made him leave Will for long periods of time. Although Nico comforts Will and they Iris message frequently, Will is afraid to be alone and is scared that Nico is going to move on before Will is ready to.
Now, Annabeth and Percy decided to go to the concert of a new singer and when they realize who it is, everything becomes more complicated.