Ragnarök

A fifteen-year-old foster kid, Mason, is willing to do almost anything--keep any secret--to avoid being plucked from relative comfort and dropped back in "the system." Meanwhile his guardian of four years, an old widow named Mildred, has secrets of her own buried so deep not even she can retrieve them. Together they uphold a code of tedious seclusion, thwarting the prying eyes of their small farming community--until a new classmate named Liza enters the scene, with about as much capacity for subtlety and discretion as a hydrogen bomb.

TWs, CWs, all the Ws apply. This is a deranged book where plenty of deranged things happen.