Surviving and finding a safe place to lay her eggs is difficult for Hypsilophodon with dinosaurs like Tyrannosaurus Rex around. When she falls into a mysterious pool and finds herself on a modern farm there are still problems. Finally she finds a safe place to hatch her babies, but how can she keep thirteen baby dinosaurs safe and secret? When the farmer catches one - Hector - and plans to take him to the vet, it's up to Hypsilophodon and her fiesty daughter, Henrietta, to get him back. After a daring rescue, Hypsilophodon takes all her youngsters back through the mysterious pool to her own world.