: MI5 agents begin openly trailing Kirsten Longacre on land, signaling that the investigation has moved beyond a simple murder case into a matter of national security.
: Wreckage from the sunk trawler Mhairi Finnea reveals that it was actually a US Los Angeles-class submarine , not a Russian vessel, that dragged the boat down while covertly tracking the HMS Vigil. Vigil 1x3
: Investigations on land by DS Kirsten Longacre and on the sub by Silva uncover a near-catastrophic incident at Port Havers, Florida 18 months prior. : MI5 agents begin openly trailing Kirsten Longacre
