It’s dawn in the damp countryside somewhere in rural Victoria. Two middle-aged brothers cycle to the farmhouse they grew up in and lay out their plans for the day. It’s a bitter return. They’re going to murder their stepdad, who they’re convinced is going to steal their inheritance.

This is Brothers’ Nest, the latest movie from the Jacobson brothers (Kenny), a new comedy that’s almost so dark it’s not funny. And it tells the story of two siblings in a confined space.

Terry (Shane Jacobson) isn’t sure about that murder plot at all. But Jeff (Clayton Jacobson) has planned it out meticulously with a blow-by-blow schedule and an obsessive cleaning roster.

Led Zeppelin had a private jet. The Jacobson brothers have a luxury bus, with “The Jacobson Brothers’ Movie Tour Bus” emblazoned on the side of it. There are comfy armchairs up front, two queen-sized bunks up back and beer on tap. They’re travelling by bus because things haven’t gone according to plan.

A few weeks ago, Shane was in Monaco celebrating Daniel Ricciardo’s Grand Prix win and hurt his leg in a flamboyant dancing incident. Doctors have forbidden him from flying, but commitments had already been made to launch their new film across the country. Hence the bus.

“If you think the film’s fucked up, you should see his foot,” says Clayton.

Shane sits opposite with his bandaged foot up on a stool, laughing. It’s not immediately apparent how these tight-knit brothers developed such a sinister story of sibling friction and manipulation. But they co-wrote it, Clayton directed it and they star in it together. Now they’re touring it together and will be on the road for several weeks. But they’re still tight.

Brother’s Nest is the first film the duo has made together since their comedy hit about a portable-toilet plumber, Kenny , was released in 2006. The film won Shane an AACTA for Best Lead Actor.

“We’ve stayed brothers,” jokes Shane. “We still go away every Christmas together.”

But working together took a backseat.

“I was pigeonholed as the comedy guy,” says Clayton. “So if I did something new with Shane I wanted it to be different.”

And Brothers’ Nest is very different to their debut feature film. It’s a tight and darkly funny chamber drama that takes cues from Alfred Hitchcock’s Rope; it involves endless apocryphal stories of family dramas turned violent, and of grand plans gone wrong. Families bring out the stupid in each other.

Clayton tells a story he heard of a father and son who conspired to burn down their pizza restaurant for the insurance money. They botched it and the son burnt his thumb off.

“The police found the thumb, and identified him, and he gave his dad up in a heartbeat,” says Clayton. “That’s the kind of world this film lives in.

“I think it’s interesting, and terrifying, that a lot of people will recognise their own families in this,” he adds. “Other than the murdering.”

There’s a bit of the Jacobsons in it, too.

“We have this amazing relationship with our dad,” Clayton says. “When he gets angry he’s hysterical. About a year ago we got into an argument in the car. I pulled over and said get out of the car. He said, ‘What? Where am I supposed to go?’ I said, ‘I couldn’t care less. Get out’. He said, ‘Well, what a dirty fuckin’ dog you turned out to be’.”

Both laugh uproariously. “And he knows,” says Shane. “This shit is going in the script, and you’re not getting a writer’s credit, motherfucker.” It does go in. That line goes to Lynette Curran, who plays the boys’ mother.

The Jacobson brothers have kept all aspects of Brothers’ Nest small and grassroots, even the funding. Before production, they approached regional cinemas to pre-purchase a stake in the film. “Cinemas were so amazing on Kenny,” says Clayton. “They got right behind it and shepherded people into the cinema.”

That’s what this bus tour is about. They’re visiting everyone who kicked money in, holding red-carpet premieres around the country. In the next few days they’re off to Wagga Wagga, Orange, Port Macquarie, then Sydney.

The reactions so far are good. “It’s reminding me of how Kenny took off,” says Clayton.

“People keep coming up and whispering to us: ‘The film’s actually really good’,” adds Shane.

“A 17-year-old said to me in Adelaide: ‘That was so good! I honestly thought it was going to be shit’,” Clayton chimes in.

It’s amazing the brothers can stand to spend more time together in such close quarters, but it’s obvious they revel in each other’s company. It’s endearing.

“I’m so indebted to my brother,” says Clayton. “We’re about to launch this film, then this happens,” he says, gesturing at his brother’s foot. “Literally four days before we’re going to come good on all our promises. Anyone else would have said, ‘Sorry, nothing can be done’ about traveling around the country.

“He would be well within his rights. But Shane’s not that kind of guy. And he’s doing it for his big brother, which is kind of beautiful.”

Brothers’ Nest is screening nationally. Watch the trailer here.