A Case for Five - The Mysterious Formula

Two professors have finally found the formula to revolutionise the world! Mankind will become more intelligent by drinking the magic liquid. At least that is the plan. A first test on the housekeeper, however, shows a completely different result: the resolute, eternally grumbling Hedwig suddenly becomes a tame, submissive servant who does everything she is told without objection. The professors are baffled. But it gets worse: no sooner have they realised that their invention is highly dangerous if it falls into the wrong hands than it disappears without a trace! It's just as well that the professor's five children are visiting their uncle. 
Here you can find the poster for the event. 

Admission: voluntary donation!