An unknown person threatened to poison the Dreisam and Bächle. The life of Freiburg residents and visitors were in severe danger. The police are on the trail of the assassin, but urgently needed assistance to prevent the disaster! The Optophysiology Lab was immediately on the scene. We went together and prevented the assassination. To celebrate the day we had mulled wine at the Christmas market and fantastic pizza at Da Giorgio. It was a successful day!