While Pat is helping Nick with his latest contract - making regular trips to Blubber Bay towing barges filled with vegetable oil - he misses another contract as Donna Lansing with Omega Chemicals, which has been doing some stream restoration work in conjunction with an environmental group called Clear Streams, wants to release salmon fry into a newly restored stream in the area. As such, Relic wrangles the Omega contract for himself. The plan for Donna and Relic to release the fry hits a snag when they learn from DFO that there is something toxic in the waters off Blubber Bay that is killing pockets of fish in the area. When Donna goes with Relic to investigate, she finds a green liquid floating on the surface, which she recognizes as a chemical toxic to fish as well as humans. She saw it coming from the Persephone and/or the barge, which implicates Nick and Pat as the culprits of illegal dumping. With help from John and others, Nick and Pat have to figure out what's going on with the...