简介：Returninghomefromacampingtrip,fourfriendspickupastrandedmotorist,whosurprisesthemallwithblastofknock-outgas.Comingto,thefournowfindthemselvesimprisonedinadecrepithousewithsixotherstrangers,andallareoutfittedwithadeviceattachedatthebaseoftheskull.Unsurewhattheyaredoingthereandwhoisbehinditall,thegroupissoonenlightenedbyvideothatadvisesthemthatthereisawayoutofthehouse.Butthethresholdtheymustcrossisoneofexcruciatingpain...Themechanismstheywearareforcollectionofchemicalsnaturallyproducedbythehumanbrainoncethevialsarefilled,thecaptivesarefreetogo.Unfortunatelyforthem,theonlywayforthebodytosecretethepreciousfluidistoexperiencelife-threateningpain.Plus,thereisa24-hourwindowinwhichtosecuretheirfreedom;afterthat,thedoorsarelockedforever.Atfirst,thereisuncertainly,andevenabotchedattempttoremovethedevice,butasolutionisdevisedeachmustsubmittoatorturesessionuntilallhavebeensubjected,andthecollectedfluidlevelsrisehighenoughtoensuretheirrelease.Inthefaceoftorture,however,noteveryoneiswillingtoplaybythenewlycreatedrulesthegroupisrippedapartbyinfighting,secretalliances,double-crossesandshatteringoutburstsofviolence.Withtheclocktickingdowntheminutes,theoneforallmentalitydevolves...justhowfarwilleachgoinordertosurvive?…