Forever Plaid, Marriott Theatre in Lincolnshire. In Stuart Ross and James Raitt’s musical, the Four Plaids are a squeaky-clean doo-wop group who had the good sense to die early–in 1964, when they collided with a bus full of “parochial virgins” headed to a Beatles concert. The public’s switch to rock would have consigned these tuxedoed dinosaurs to Kmart openings anyway. Given a last chance to perform the concert they never lived to give, the lovable losers deliver a 95-minute salute to cheesy lounge acts everywhere.

But despite groaner jokes, clumsy segues, cheap props, forced “Plaid-itudes,” and stiff introductions, this less-than-fab four really does find harmony heaven, bringing it to earth in such feel-good standards as “Three Coins in the Fountain,” “Catch a Falling Star,” and “Love Is a Many-Splendored Thing.” Directed by Rick Boynton (who performed in the original Wisdom Bridge productions), Forever Plaid honors the power of nerds to unleash a flood of nostalgia.

The crowd ate up every chord, especially Paul Castree’s heartfelt solo in “Cry.” They whooped it up over a hilariously condensed version of The Ed Sullivan Show, performed to “Lady of Spain.” They melted over the Plaids’ ham-handed tribute to the night Perry Como heard them croon. Daniel Cochran, the group’s cheerleader, joins dorky/hunky Jim Weitzer in a pseudomacho rendition of “Sixteen Tons.” And Cullen R. Titmas is Sparky, the garage monkey with a heart–and voice–of gold.