▁r ats ▁must ▁be ▁behind ▁everything . ▁The ▁Al chem ist , ▁upon ▁hearing ▁this , ▁reve als ▁that ▁the ▁whole ▁thing ▁is ▁his ▁fault ; ▁long ▁ago , ▁his ▁experiment ation ▁on ▁the ▁r ats ▁had ▁caused ▁them ▁to ▁evol ve ▁and ▁prosper , ▁and ▁when ▁they ▁became ▁too ▁demand ing , ▁he ▁fl ushed ▁them ▁into ▁the ▁se wer . ▁He ▁then ▁tells ▁C live ▁there ▁is ▁only ▁one ▁who ▁can ▁help ▁stop ▁the ▁r ats : ▁Isabel la ' s ▁ex - boy friend , ▁the ▁P ied ▁Pi per . ▁ ▁C live ▁makes ▁his ▁way ▁to ▁the ▁pub , ▁where ▁he ▁finds ▁the ▁P ied ▁Pi per . ▁Upon ▁inform ing ▁him ▁that ▁the ▁r ats ▁are ▁responsible ▁for ▁the ▁pl ague , ▁the ▁Pi per ▁resol ves ▁to ▁take ▁the ▁action ▁to ▁stop ▁them . ▁( Pay ▁the ▁Pi per ) ▁However , ▁the ▁Rat ▁King ▁has ▁already ▁anticip ated ▁the ▁move ▁and ▁k ills ▁the ▁Pi per ▁with ▁a ▁bo oby - tra pped ▁se wer ▁explos ion . ▁ ▁The ▁Rat ▁King ▁then ▁amb ush es ▁C live , ▁Jerry ▁and ▁Mil ly , ▁t ying ▁them ▁up ▁and ▁inform ing ▁them ▁that ▁the ▁age ▁of ▁rat ▁has ▁begun , ▁and ▁that ▁r ats ▁will ▁take ▁the ▁humans ▁place ▁in ▁London ▁once ▁they ▁are ▁gone . ▁ ▁All ▁seems ▁lost ▁but , ▁thanks ▁to ▁the ▁tim ely ▁assistance ▁of ▁the ▁begg ars , ▁the ▁hero es ▁escape . ▁C live ▁confront s ▁the ▁Rat ▁King