Isaacisthenewkidintown.Hismother,Vera,isinthehospitalwithamysteriousillness,andtheonlypersonlefttocareforIsaacishisdistantgrandfather.Friendlessandoftenalone,Isaacloseshimselfinhiscollectionofopticalillusions,includingastrangemirrorboxthathefindsinhisnewhouse,leftbehindbytheprevioustenants.Designedforamputees,itcreatestheillusionofasecondlimb.LonelyIsaacwishessomeonewouldreachouttohim,andthensomeonedoes—aphantomlimbwithinthemirrorbox!ItsignstoIsaacaboutagrowingdanger:someonewhohasmurderedbeforeandisouttogetVeranext.TheonlywayIsaaccansolvethemysteryandsavehismotheriswiththehelpofthemirrorbox.Butcanhetrustthephantomlimb?