The classroom is astonished when their teacher tells them his big secret: sometimes he turns into a frog. Two kids see it as their task to protect his secret.. and to keep him out of the beak of a stork.

Franz is devoted to his Dutch primary school class, but his unconventional methods displease mean, old-fashioned headmaster Stork. During science class, pupils Wouter and Sita find out his stunning secret; he sometimes turns into a frog, so the try to help him cover up and avoid being eaten by a stork, especially an equally surprising counterpart shapeshifter at school.—KGF Vissers