Sink or Swim (S01E04)

The eight adventurers are deep into their expedition's fourth leg, facing the challenges of the Talachulitna River's treacherous currents. Navigating the icy waters proves to be quite the ordeal. To secure food, seasoned climber Willi Prittie joins forces with Iditarod champion Dallas Seavey and his brother Tyrell. At the same time, mountain man Marty Raney and his son Matt decide to enter the river further downstream, aiming to reduce their time spent battling the swift waters.