While Dave Thomas battles with research and teaching deadlines, out in Mauritius, John Turner braves shark- and barracuda-infested waters to investigate threatened coral reefs.
Back in north Wales the first-year students discover the joys and hazards of kelp.
A group of second-year students takes to the high seas to experience life on board the department's research vessel Prince Madog.
Back at base everybody waits by the fax machine to find out whether the application to replace Madog has been successful.
Gary faces a crisis of confidence just before his finals.
While on a remote lough in Ireland, a team of divers from the university deals with the twin terrors of giant lobsters and surviving for three weeks on their own cooking.
On a beach in Chile the team investigates a case of poisoned mussels and a pollution problem.
Back in Wales Niall has a new love in his life - Rosie the motorbike.