TV Guide National Geographic Channel Tuesday

Oakland, the eighth-largest city in California, has an out-of-control drug trade, but its detectives still work around the clock to bring down the ringleaders.

A dealer buys large quantities of heroin and drives up I-95 to sell it in Baltimore; an addict runs an unsanctioned cab service to earn drug money.

A former British gangster guides the crew to a hash factory in the mountains; customs agents near Gibraltar seize 100 kg of hash and barely impede the flow.

Various celebrities spend time in Las Vegas, and they go on a search for drugs of different types that would allow them to engage in a variety of activities.

A growing dispute between two cartels impacts the escalating drug trade within the city of San Francisco as each group battles for control of the markets.

A 27-year-old dealer has sold drugs for 15 years; the Chicago Police Department's violent crimes unit hunts gang leaders; two heroin users get by.

Alaskans must work day and night in order to ensure their survival.

Arctic residents must persevere no matter the hand they are dealt.

Residents of Port Protection emerge from winter with their paths forever changed; Oliver and Breanna take to the water for fresh protein.

Carl stalks a deer; Troy braves the cold water on a dive; Curly and Mary tear down a dangerous structure; Veronica tries her first solo tree falling.

Winter continues to pummel Port Protection and some venture out to find food for their families; Carl spots a buck in his crosshairs.

Curly lends his expertise to help remove danger trees from above Jiggy's house, but a broken safety cable turns things deadly serious in an instant.

As Mother Nature tries to take back the land, Port Protection residents work hand-in-hand to ensure the safety and success of the community.

Sam and Squibb ascend a decaying boat roof to salvage a heavy mast; Oliver searches for an abandoned boat for a crucial piece.

Hoping to add a new weapon to his fishing arsenal, Oliver hits the water with Carl, Matt and a new set of slinky pots and they're in for a shock.

Milestone achievements are only possible with steep challenges in Port Protection; Carl and Matt pull a 3,000-gallon barrel up a cliff.

With the help of Troy and Sarah, Squibb tackles a ticking timebomb that threatens to kill all life in the Bay.

Port Protection takes advantage of summer weather; Curly Leach spends some final moments with a dear old friend, leaving for an easier life back on the grid.

The villagers of Port Protection are back to paving with good intentions.

In Port Protection, the old guard passes on wisdom to a new generation.

Alaskans have a brief window to harvest vital resources to sustain.

The villagers of Port Protection are back to paving with good intentions.

When a truck crashes into a snowbank in the mountains, Thord and rookie Terje must put their lives at risk to save its valuable cargo.

At the onset of the winter season, Alaskans face new threats to their survival, but the dangers of the Arctic year have only just begun.

As winter rages on, Alaskans must adapt to increasingly erratic weather to survive; Sue Aikens stockpiles meat before the caribou herd migrates.

As the deep cold of dark winter persists, Alaskans must become one with the land if they are to carry on their way of life; Johnny hunts for a food source.

As daylight fades, Alaskans contend with the animals and predators lurking in the shadows; Sue Aikens investigates a looming threat in Kavik.