Human beings love to find patterns in events, even if none exist. It’s hard-wired into our brains, and explains our love of conspiracy theories, long-buried secrets and other attempts to put a sane façade on impossible-to-comprehend events.

In Glen Berger’s "Underneath the Lintel," a nameless Dutch librarian thinks he has found an absolute doozy of a long-buried secret, all starting when a book comes in that is more than a century overdue. From there, the story he discovers -- or just creates -- dominates his life.

In the hands of veteran stage, TV and film actor Pat O’Brien, the Librarian is a confused, stumbling and sweating mess who only wants others to hear -- and believe -- his story. In O’Brien’s self-mounted production, playing through July at the Mixed Blood Theatre, you are never sure what’s truth and what’s fancy as you follow the Librarian’s twisting tale.

Berger’s script never comes down firmly on either side -- is it a true tale uncovered by an unlikely explorer; or just the ravings of a man driven mad by his life? At first blush, the tendrils seems plausible, but as the character spins deeper and deeper into his own rabbit hole, questions arise about the daisy chain -- linked together by ancient receipts and vague accounts -- that bring it all together.

O’Brien -- probably best known as Mr. Dewey on "Saved by the Bell," but who also has a long list of film and theatrical credits -- thrives in the show’s ambiguity. The character is far from graceful, pacing around the stage while using slides, music and other props to tell his tale. As the character’s story becomes more and more fantastical, O’Brien’s performance becomes more and more unhinged, showing us the battle that rages between the reserved Dutch librarian and the mad world traveler.

"Underneath the Lintel" is a brisk journey into the unknown that rewards careful attention. It’s also often funny and allows O’Brien -- and in turn the audience -- to dig deep into a flawed and lonely character.

"Underneath the Lintel" runs through July 25 at the Mixed Blood Theater, 1501 S. 4th St., Minneapolis. Tickets are $15. For more information and tickets, call 612-338-6131 or visit online.