Season 3 follows the investigation into the sinking of a sea ferry, The Queen of the Narrows. It's a beautiful day in Boston when almost 500 passengers board the ferry destined for Newfoundland, Canada. A few hours into the journey an “explosion” onboard throws passengers into a panic and the ferry sinks in record time. This has the whiff of a conspiracy, but is that really the case, or is this just another incident? Dominic Hayes (Kris Holden-Ried) and Kendra Malley (Archie Panjabi), two investigating officers, are tasked with uncovering the truth.