by Margus Paju
Mari and her three friends love nothing more than putting their instincts to the test by taking part in paper chases and treasure hunts. Their self-titled ‘secret society’ has not yet failed to solve a single tricky mystery thrown at it by Mari’s cunning grandfather. One day a mysterious illness that causes adults to act like children breaks out in the town of Tartu. Left untreated, the illness leads to certain death within 48 hours. Doctors are completely perplexed. The four friends, however, learn through Mari’s grandfather that an antidote exists. So the ‘secret society’ sets off on an adventurous search for the elixir, but the children have no idea that a mysterious and dangerous masked figure also has his eye on the precious remedy.
