Dean and the crew head to Middleton Reef. On the journey, they are becalmed and take a mesmerising ocean swim in water that is 4 and a half kilometres deep.

A Tiger Shark has bitten the back of the boat and is still hanging around. The crew have to summon up the courage to get back in the water.

Bad weather forces Dean and the crew back towards the Australian mainland. Dean takes his camera into the middle of a bait ball with dolphins and seals.

The crew dives with endangered Grey Nurse sharks that Dean's dad Ben had hunted back in the 1960's. After a couple of crew changes, the expedition moves to Cato Reef.

Without safe anchor, Dean voyages on to Saumarez Reef and As the expedition heads north, closer relationships start to form between crew members.

Next stop is Marion Reef. Lauren is not looking forward to it. Marion is famous for sea snakes and her snake phobia has not improved.

Dean takes the crew towards Carola Kay, a place of personal significance for him. Dean's father Ben, gave him his first cinematographers job at this special location.

Wanting to make new discoveries, Dean takes the crew to a reef his father has never visited, Lihou Reef.

Food is running out and it is time to head back to Cairns on the Australian coast. The voyage back leads to encounters with Humpback Whales and glowing dolphins at night.

Anika survives her shark bite, but the tourism authorities doubt her story and she is trolled on social media.