Outstanding SP but without Karou. Professor Yukawa was certainly on top form. He had two difficult mysteries to solve and both were good challenges. His experiments to confirm his theory were impressive and well executed. It was fun to see him act out to find the evidence. Like most of the murders in these series, there was a sad motive behind each. Karou's substitute tried but was never a threat to replace her. Never a dull moment. This episode is well worth seeing. Naturally accompanied by the good ost. Strongly recommended.