Thirty-two-year-old Sibylla Forsenström has long broken with her wealthy relatives, and with society as a whole. She spends the night either in basements or in attics; all her belongings fit into a small backpack. And then one day, being in the wrong place at the wrong time, a woman unexpectedly becomes the main suspect in a monstrous murder involving organ theft. The entire Swedish police are hunting for her, and in the meantime more and more murders are happening. And Sibylla has no choice but to conduct her own investigation and find the killer herself, figuring out his motive through a chain of mysterious losses.