Miss Mary-Kate Martin might be anxious, but she's not scared of monsters. Mary-Kate and her mother are visiting Galinios, an idyllic Greek Island filled with history and surrounded by the shimmering Aegean Sea. An ancient mosaic has been unearthed at the local sardine processing plant and Professor Martin must investigate, leaving Mary-Kate to enjoy a few days of sunshine. But a message asking for help changes everything. A wrecked boat and smashed jetty have recently disrupted life on this tranquil island and point to a monster-sized mystery. Could the local legend of the Two-Headed Hydra be more than a story? If so, what could have made this historically serene sea creature so angry? Armed with her glitter pens and strawberry-scented notebook, Miss Mary-Kate Martin is determined to find some answers

"Full of humour, fantasy and magical realism... the ideal story for early readers" - Better Reading

"Another brilliant instalment in this fantastic middle grade series... so much fun and very addictive, pulling in readers all the way through" - Kids' Book Review