After the death of his father and three out of his four siblings, Killua was diagnosed with a schizoaffective disorder. And the less he takes his meds, the more he's unsure of reality. And the more he's unsure of reality, he might as well have died with his family. But upon meeting Gon Freecss, the kindest teenage boy around, his life starts to turn up, even if just a little. He's feeling less depressed, less moody, less suicidal, less horrible. But his meds are off the table. Gon is his medicine, his forever medicine. He could be cured and not temporarily fixed. But as the weeks off his meds drag by, Killua becomes more and more confused as to what's real and what's not.