Basedontheactual11-daydisappearanceoffamedmysterywriterAgathaChristiein1926,thefilmfictionalizesherwhereaboutsduringthattime.Whenherhusbandannouncesthatheisleavingherforanotherwoman,ChristiecreatesamysteryoutofherownlifebyhidinginaHarrogatehotelandplottingrevengeonherspousewhileallofEnglandsearchesforher.ThereporterwhofindsChristietriestofoilherplanandfinallyfallsinlovewithher.