Setting sail to the magical island of Bali, Steve and the team are out to find the elusive ocean sunfish. These deep ocean giants feed on poisonous jellyfish and ascend to the shallows for a spa session at a cleaner fish station. Strong currents provide challenging conditions, and the dives have to be abandoned after the team run out of air, putting the hunt on hold!\n\nHeading inshore, Steve dives by a shallow reef to see what deadly contenders he can find. First is a lionfish, a beautiful but deadly predator with venomous spines and a lethally fast strike. Next, Steve comes across a pair of frogfish. These bizarre-looking fish have incredible camouflage and are among the best ambush predators in the ocean, blending into the reef and waiting for lunch to swim by before pouncing. The frogfish are extremely inquisitive and take up residence on cameraman Mark's camera.\n\nThings turn serious when Steve discovers a ghost net choking the reef. The discarded fishing net is causing havoc – trapping a trumpetfish and stopping it joining its mate, and smothering an anemone and its resident clownfish.\n\nBali is facing many environmental challenges, but it is taking a strong stand against plastic pollution, as many ocean animals are highly affected by the plastic in our seas. For the sunfish that prey on jellyfish, it can be fatal, as a plastic bag looks identical to their prey. The programme features the two young founders of Bye Bye Plastic Bags, who in January this year got the Balinese government to completely ban plastic bags on the island. Heading out on a beach clean-up and out into the ocean, Steve helps the island continue to keep their oceans and beaches clean.