Setinasmallisolatedvillagein14thcenturyWales,Aliceisasixteenyearoldgirlwhoisaccusedofbeingawitchandcausingtheplaguethathasravagedthevillage,takingthelivesofmany,includingAlice'sownfather.WhenitisrevealedthatAlicehasbeenhidinghermother'sinfection,sheisforcedtowatchTheCleanser,anominousmaskedfigure,brutallydispatchhermother.Thetownpreacherandde-factoleaderTomhaseyesforAlice,andsubjectshertofivetorturoustrialsaftershespurnshisadvances.Escapingthenightbeforeherexecution,withthehelpofhermother'sfriendMary,shefleesintotheforestanddiscoversthesecludedhutofamysterioushealer,withhisowntroubledpastanddemonstoface.Henursesherbacktohealth,andteachesherhowtoexactrevengeuponthosethatpersecutedher.