A ""tricky little case"" With ""bad business"" sends Inspector Baker to a British science convention in an effort to trap defecting scientist Mervyn Marsland. The tactical plan is to substitute one of the Yard's men for Marsland when he makes his escape. But the substitute is murdered (mistaken identity?) and the little scientist is off...leaving an assortment of bodies along the trail. It's nip and tuck and neatly handled.