Old people. Is there anything funnier? They do the craziest things, like hoard, stalk and post on conspiracy sites. But if you need to borrow a few batteries or a canned tuna, there’s no better source. They also seem to easily fall in love to the strains – and I mean strains – of “Muskrat Love.”

Or, at least they do in the mind of writer-director Noble Jones, whose truly bizzaro “The Tomorrow Man” will either leave you giddy with its unmitigated devotion to quirk, or have your eyeballs on a continuous roll in reaction to a seemingly endless string of ridiculous contrivances. Oh, and did I mention there are nuclear bombs?

It’s “The Day After” meets “Cocoon,” and how you feel about such an odd mix will go a long way in determining if “The Tomorrow Man” is worth a grin or a groan. Me? I’m smack-dab on the fence. I’m gaga over the brilliant pairing of John Lithgow and Blythe Danner as eccentric lovers blindly diving into a second-chance romance, but weary of all the baggage Jones has strapped to their backs. They can lug it only so long before the spines of their characters snap.

Jones seems to know it, which might explain the marvelous second-act change-up he throws over the plate during a hilarious Thanksgiving dinner that feels like an entirely different movie, one infinitely more fascinating than the other 75 minutes of leftovers. Suddenly, Jones’ script becomes excitingly alive, as Derek Cecil and Sophie Thatcher spring to the fore as Lithgow’s highly dysfunctional son and granddaughter. They inject anger and insults aplenty in an all-too-brief exchange that hits you like an electrical charge to the soul. You cringe, you laugh and you thank God for finally being fed something other than the somnambulance of two, weird septuagenarians stumbling into love like a pair of naive 13-year-olds.

It’s a testament to Danner and Lithgow that they’re able to sell such nonsense so convincingly. But you have to wonder if they saw the script before they signed on. And if they did, why the need to make baby boomers look like complete idiots? Frankly, I was creeped out initially, as Lithgow’s Ed Hemsler spends the first 10 minutes of the movie stalking Danner’s Ronnie Meisner in a grocery store. How Ed is able to be in said store at the same time as Ronnie day after day is a case study in perfect timing. Even better, he never fails to be lurking directly behind her when she enters the checkout line; often making strange comments about what she’s buying.

You and I would run – not walk – to the nearest security guard. Not Ronnie. She seems oblivious to the strangeness of a stranger who is THERE whenever she turns around. Eventually, Ed strikes up the nerve to ask her out. Instead of calling a cop, she accepts. It’s one of those moments that could only occur in the mind of a misguided screenwriter, but you go along because it’s Danner and Lithgow, two of Broadway’s brightest lights. You even grant them a mulligan or two, as their characters awkwardly bond over the end-of-the-world fantasies Ed’s just gleaned off the Internet.

The kicker is that Ed is convinced Ronnie is a tin-foil-hatter just like himself. Hint: She’s not. She’s merely utterly clueless, which really makes you wonder why Danner wanted to play a person more in need of psychiatric care than a conspiracist boyfriend obsessed with stocking up on batteries and canned tuna. Oh, and the less said about Ronnie’s closely guarded secret the better, especially when Jones treats it like an idiosyncrasy instead of the full-blown mental illness it is.

As a former assistant to David Fincher, you see where Jones gets his love for the offbeat. But, sadly, he’s no Fincher; except maybe during that aforementioned Thanksgiving scene in which Ed brings Ronnie home to meet his seriously screwed-up family. There, Jones, who serves as his own cinematographer, is really on to something alive and invigorating. But 10 minutes later, it’s back to the Ed-and-Ronnie grind. Only in the final minutes – after the obligatory break-up and make-up – does Jones again reach his true potential with a knockout final shot. It’s so great, it almost redeems him and his movie. But like Ed and Ronnie, the rest is old, tired and borderline insane. Ain’t strange love grand?

