Two years on since Monty Halls, his wife Tam and daughters Isla and Molly first travelled to the Galapagos islands, the family head back to discover why it faces a fight for survival. In the opening episode, Monty experiences the mighty volcanic power that created the islands, mum Tam makes a solo voyage in search of threatened giant manta rays, and Molly, the youngest, has her first snorkelling experience.

Marine biologist Monty Halls and his family are settling into life on the island of Isabela in the Galapagos, where they discover it's not without its challenges. The family find flamingos in an unexpected place and get to know a big fish with a bad reputation. Daughter Isla becomes a young field assistant helping to tag baby Hammerheads, while Tam and Monty mark their wedding anniversary underwater with over 20 endangered sharks.

Monty goes on an expedition to rescue a sea lion. Tam, Isla and Molly investigate marine plastic and learn how tourists can help look after these islands for future generations.

As their stay on the Galapagos draws to a close, Monty and his family find out what's being done to protect the islands and their wildlife from the threat of invasive animals