The Amish Mafia's and Levi's biggest secrets come to light.

The Twetos brave the elements to deliver supplies to inaccessible areas.

Jim arranges to transport the casket of the dark winter's first casualty.

The Tweto family takes full advantage of Alaska's summer conditions.

The pilots brave the elements as hurricane-force winds roar into Alaska.

A Greenhorn pilot goes on the most challenging run of his short career.

The guys cope with an influx of teachers after the first snow.

Pilots embark on two white-knuckle flights involving something explosive.

Ariel's flying lessons end in disaster after a hard day of work.

Ariel attempts to learn the family business as Halloween takes over Alaska.

Luke takes on a daring rescue as winter's darkness overtakes Unalakleet.

Turbulence and angry passengers make for a long flight through Nulato.

Two pilots land vaccines on a treacherous runway two miles from Russia.

Luke delivers the first-ever ATM with a planeload of cash to Wainwright.

The team gets busy as Alaska recovers from two months of darkness.

The Twetos get a business bump when the Iditarod dog sled race hits town.