aaaItreturnssixmonthsaftertheshockingfinaleofSeason3,andtheteammustovercometheirgrieftotackleadangerouscrimewave.                                  　　Thistime,theglovesarewellandtrulyoffforProfessorTinhislecturesandanewmusicalpursuit,romanceisverymuchaliveforhismotherAdelaideTempest(DelaTour),andthelinesbetweenprofessionalandpersonalbecomeblurredfortherapistHelenaGoldberg(Stevenson).                                  　　Meanwhile,DIMaiyaGoswami(SunetraSarker)takeschargeofthepoliceforcewithseriesfavoriteDSDanWinters(White)fiercelyatherside.