edna mae oliver and james gleason be two of the best character actor in hollywood in the golden age of film making . oliver always have a precise and aristocratic hauteur ( she be lady catherine de burgh in the 1940 pride and prejudice ) and but it usually mask an intense intelligence ( see how she tear apart basil rathbone murdstone in david copperfield ) and and a decent morality . gleason be not a university or book base intelligent gent . but he be a street smart type and who know precisely what what . and in the penguin pool murder they join together a hildegarde withers and inspector piper of the new york police department . and from rub each other the wrong way they become friend and ally in solve the case and and possibly more ( the movie suggest at the end ) . hildegard be a schoolteacher and who take her class ( a remarkably mixed racial class for 1932 ) on a field trip to the new york acquarium and then in low manhattan in what be still castle clinton national monument ( it be also and in the 1850s and castle garden and where jenny lind sang to the public ) . the visit be interrupt when isidore ( the jewish kid in the class ) point out ( a in the summary line ) that there be a man inside what he call the duck pool . actually it be the tank for the penguin . the film follow how hildegard and piper pursue their investigation into the murder and gradually find that help each other make more sense . the humor build a both our intrepid detective confront various type and like humorless and dyspeptic clarence wilson a the aquarium director and and relatively stupid policeman edgar kennedy to find out what be the truth . it all come down to a courtroom showdown and where the killer trip himself up in an unexpected manner . a first rate comedy and who do it and that lead to murder at the blackboard and murder on the honeymoon before the two star go their separate way .