The Nerd — so goofy, he’s dangerous.

Opening night, Cygnet Theatre: during the first 20 or so minutes of Andrew Bovell’s When the Rain Stops Falling audience members shuffled in their seats and sporadic coughing broke out. The intermissionless piece plays like story theater — while actors perform, the others sit and watch in an essentially static stage picture. Been there, done that. But after 20 minutes the squirming stopped, the story took hold, and the theater grew so quiet you could hear a tear drop.

It’s important that the characters in Rain not in a scene remain visible. They represent the past and the future. One talks about “some kind of parallel time frame.” This technique makes the events of eight decades not only feel similar, since coincidences abound, but inescapable.

Watching Rain is like watching a photograph slowly develop. No, make a series of photos from different periods of time. Parts come clear over here, a few over there. But as they jump back and forth they don’t seem to connect. Then certain shades repeat, shapes evolve and intertwine on unforeseen levels.

Rain tells about four generations, the Law clan in London and the Yorks in Australia, from 1959 to 2039. Two of the men have the same name, Gabriel (one’s a Law, his son’s a York). Complicating matters: a woman’s called Gabrielle (she’s a York, Gabriel’s mother). In most scenes, which decade-hop in nonlinear fashion, either it’s raining or a brutal storm’s on the horizon. Right off the bat, a fish falls from the sky and lands at Gabriel York’s feet in 2039, this around the time he says, “I do not believe in God. I do not believe in miracles.”

As the scenes unfold, the connections link the years more deeply. Rain plays like the “sins of the father” in Greek tragedy, but without the gods. The revelations are so stark, the script should have a warning to critics: “Do not reveal.”

So let me be vague. The playwright is Australian. One feature of Rain recalls Peter Weir’s eerie 1977 movie The Last Wave. Behind a backdrop of daily life in Sydney, Australia, bizarre rainstorms augur an apocalypse only the Aborigines see coming. An Australian audience watching Rain when it premiered in 2008 would make the connection.

Rain may begin at the end of the world, due to the sins of civilization? Gabriel York read a history book, The Decline and Fall of the American Empire, 1975–2015, and climate change is flooding coastlines around the planet. Amid this last-times backdrop, the play traces an 80-year cycle of pain. Fathers (and sons) “wander”; wives remain behind with clobbered dreams. But is it the end of the world, or finally the end of a toxic family cycle? Or one amid the other?

Cygnet’s production is stellar. Under Rob Lutfy’s acutely sensitive direction and Michael Mizerany’s graceful choreography, the cast alternates from fluid movements to stillness in ways that verge on the hypnotic. Though the abstract set’s a puzzle — drab bare stage with red piping and a heavy cloud overhead that looks like a big potato — the rain effect enhances scenes, as does Kevin Anthenill’s ever-present, but never intrusive, watery music.

One of my barely legible notes says, “Adrian Alita should get out (of school) more.” He’s the head of acting at SDSU and he’s terrific as Gabriel York and Henry Law, the fathers who bookend Rain. Gabriel’s opening monologue — what can a father give a son he abandoned as a boy? — charms and stuns in like measure.

Watching When the Rain Stops Falling is like watching a photograph slowly develop.

Prophecy runs throughout Rain. Rosina Reynolds and Tom Stephenson, as Gabrielle Law (for some strange reason pronounced “Gabriel”) and her husband Joe Ryan, have a one-sided marriage predicted 25 years before. Like many of the characters, she’s stuck in a self-image prison (“you weren’t meant to be happy”) and can’t break out; he offers unreciprocated adoration. The result, in one of the production’s finest scenes, is a profoundly haunted sadness.

Cristina Soria and Beth Gallagher, impressive as the older and younger Elizabeth Law, are also trapped. When Mount Tambora exploded in Indonesia, in 1816, it created “The Year Without a Summer,” which people feared was the end of the world. Although young Elizabeth says, “It will take more than a spot of bad weather to silence the human mind,” an explosion in the family prevents her older self from retaining that optimism.

There are traps for those who break away. The young Gabrielle York (Rachael VanWormer, achingly torn) and Gabriel Law (defiant Josh Odess-Rubin) have a chance to escape from the past and the pattern laid out for their lives. But, they learn, you shouldn’t flee too fast.

When the Rain Stops Falling, by Andrew Bovell

• Directed by Rob Lutfy; cast: Tom Stephenson, Rosina Reynolds, Adrian Alita, Beth Gallagher, Cristina Soria, Rachael VanWormer, Josh Odess-Rubin; scenic design, Jungah Han; costumes, Jeanne Reith; lighting, Chris Rynne; wigs/make-up, Peter Herman; sound design/composer, Kevin Anthenill
• Playing through February 14; Wednesday and Thursday at 7:30 p.m.; Friday and Saturday at 8:00 p.m.; Sunday at 7:00 p.m.; matinee Sunday at 2:00 p.m.

Lamb’s Players has staged Larry Shue’s The Nerd before, and David Cochran Heath has starred as Rick Steadman, a Rip Van Winkle from the Twilight Zone so goofy he’s dangerous. Heath’s back and hasn’t lost a quirk, be it fidgety hands, as if trying to shake off something icky, or that innocent-doofus gaze, behind which lurks a mind made of Flubber. Not to mention Heath’s crack timing and artistic generosity with a fine ensemble cast under Robert Smyth’s direction.

Rick Steadman pulled a wounded Willum Cubbert (Mike Buckley) to safety in Vietnam. Willum, a non-conbatant, was unconscious when rescued. Though they have corresponded, the two have never met. Now friends say Willum’s lack of “gumption” hurts his career as an architect.

The friends are Tansy McGinnis (Cynthia Gerber), a weather forecaster with eyes for Willum, and Axel Hammon (Brian Mackey), a theater critic in Terre Haute, Indiana. Along with wanting a more assertive Willum, Tansy wishes that, just once, curmudgeon-ish Axel would do an unselfish act.

That’s the set-up. What follows is a two-act steeplechase that also involves the Waldgrave family (John Rosen, Susan Clausen, young Scotty Atienza), as wealthy as they are dysfunctional. Willum must generate sufficient gumption to evict the man who saved his life.

Mike Buckley succeeds with Willum, which could be a difficult role, having to make a passive personality interesting. Buckley also designed the handsome set, which Rick Steadman appears bound and determined to destroy.

The Nerd, by Larry Shue

• Directed by Robert Smyth; cast: David Cochran Heath, Mike Buckley, Susan Clausen, Cynthia Gerber, Scotty Atienza, Brian Mackey, John Rosen; scenic design, Mike Buckley; costumes, Anna Marie Phillips; lighting, Nathan Peirson; sound, Patrick J. Duffy
• Playing through February 14; Tuesday through Thursday at 7:30 p.m.; Friday and Saturday at 8:00 p.m.; matinees Saturday at 4:00 p.m. and Sunday at 2:00 p.m.