The winter season has begun and Emily finds herself without a permit while the Kelly brothers begin to mine sans father Brad who has his own small operation right beside them. Meanwhile, Shawn takes a big risk as he heads miles out of town to search for gold in a remote area called the Bluff and Vern experiments with an untested digging machine called a sub-dredge.
Emily is accused of negligence by a greenhorn who quits on the first day while the Wild Ranger's new sub-dredge has mechanical difficulties. Over on the Bluff, Shawn is the first human to dive in the remote area and realizes it's very different than mining on Nome Harbor.
Shawn runs out of fuel and sets out on a dangerous trek to a remote town for more supplies while Kris Kelly deals with an equipment breakdown on the Paddy Wagon. Meanwhile, Emily loses the trust of her crew when she reacts poorly in an emergency situation.
Steve makes a surprise appearance at the Bluff to check his son's progress and the Kelly brothers have a heated argument that threatens to split them up for good. On the Clark, Zeke is frustrated with the progress of Emily's greenhorn crew and one of Vern's divers on the Wild Ranger has an underwater emergency which leaves the team at a crossroads.
With only one week left of winter mining a huge blizzard surges into Nome severely limiting the crews from getting on the gold. Over on the Clark, Zeke brings back his brother Gabe to help save the dismal season and Kris Kelly is dejected to find the Paddy Wagon filled with snow. Meanwhile, Vern's sub-dredge leaks oil signaling to Vern that the season has come to a premature end.
The final day of winter mining brings all crews out early to search for gold but the Kellys are forced to shut down prematurely when their equipment is stolen. On the Clark, Emily and Zeke weigh the pros and cons of continuing their working relationship while Shawn Pomrenke fights poor visibility to catch as much gold as is possible before the government shuts them down.