When Emily's mother becomes dangerously ill again, in this sequel to 'Tolly and the Pirate Ghost',Emily and the twins, Laura and Harry, time travel with Tobias, the pirate ghost, and his parrot, Tolly, to a tropical island in the year 1660. Their goal is to find the legendary Medicine Tree said to cure any illness, but there are thousands of trees on the island. How can they possibly find the right one?
Tobias is reassuring but mysteriously disappears with Tolly, shortly after their arrival, leaving the children to fend for themselves under a scorching sun, with little to eat or drink and no means of getting home. Their problems multiply when they realise a band of ruthless pirates is also hunting for the Tree, and will stop at nothing to gain the prize and make their fortune.
Time is running out to save Emily's mother and dangers press in on all sides. As the situation becomes desperate, the children start to quarrel and then to lose hope. More complications arise and their spirits are in turn raised and then dashed. Can they think of some means of escape or will they be trapped forever on a tropical island hundreds of years in the past?