The Monstrous Monster of the Deep, a giant eel, captures young Cornet in revenge for the eels he has caught. Cornet's inventor sister, Angelica, sets off underwater to rescue Cornet and eventually, aided by Coral and Co. of the Military School of Fish, achieves her goal and makes an unexpected friend. This is a charming and funny play for young people, full of quirky characters and a touch of surrealism.