Pan gaiff y Ditectif Jeff Evans ei alw i ymchwilio i ymosodiad ar hen gyfaill, mae'n darganfod bod rhywun yn gwenwyno'r afon leol. Ai potsiwrs sy'n gyfrifol, ynteu oes rhywbeth mwy sinistr ar droed?
When Detective Jeff Evans is called to investigate an attack on an old friend, he discovers that someone has been poisoning the local river. Is this the result of poaching or something more sinister?
