The title refers both to the sense that someone suffering from depression is in a black box and also to the boxed warnings on anti-depression drugs. Elena's world changes dramatically when her sister is hospitalized with severe depression. Her parents believe in keeping it a secret. this is a secret that everyone already knows and places Elena in a hard spot. Dora asks Elena to rescue her from her situation which Elena believes means both the depression and the hospital.
The sadness, shame, helplessness sense of responsibility are heavy burdens for Elena to bear. Although Dora is older, Elena has always been the steady one who watched out for her sister. Jimmy, an odd kid who has failed at least one grade reaches out to Elena, befriended her, tried to help her while keeping his own secrets. The climax of the story Elena and Jimmy searching Dora's room after Dora returns home and find a stash of drugs Dora has hidden and discover that Dora is skipping most of her classes. After, Dora tries to commit suicide and Jimmy tells his whole story and Dora perhaps gets the real help she needs. Elena perhaps can begin to set aside concerns for Dora and live her own life but nothing is for certain in this heartbreaking story which is as it should be.