"The Sorcerer" continues through Sunday.

I can see why “The Sorcerer” is not one of Gilbert & Sullivan’s more popular works. It takes a while — at least halfway through the first act — to really get up steam. There’s not much that can be done about that; the show’s written that way. But as soon as the action starts to unfold, it’s a terrific little comic operetta.

The University of Michigan Gilbert and Sullivan Society’s version of this third G&S collaboration runs tonight through Sunday in Lydia Mendelssohn Theatre. Because of a scheduling conflict, I had to catch the final dress rehearsal Wednesday night, but that wasn’t a problem; the show I saw was definitely ready for prime time.

The story turns on a familiar G&S device — a love potion — that causes the unmarried residents of a village to fall in love with the first person they see, regardless of age or social rank, resulting in a host of comically mismatched couples.

Director Mitchell Gillett has a terrific cast for this show and he makes the most of them.

David Andrews, the sorcerer of the title, played his role as if he were born to it. His entrance marked the point where the production really took off. The G&S veteran was pitch-perfect in the patter song “My name is John Wellington Wells,” and he seemed to delight in the devilish mischief his character was causing (the red gloves were a perfect touch). “Incantation” was also compelling, and it was there Andrews got to savor some of the show’s tastier wordplay (“Now shriveled hags, with poison bags, Discharge your loathsome loads! Spit flame and fire, unholy choir! Belch forth your venom, toads!”). Jeff Wilkinson was also first rate as the young newlywed Alexis, the one who sets the love potion in motion. He has a beautiful voice that was a delight to hear, particularly during his second-act ballad. As Constance, soprano Alexandra Kahn also delivered the goods; the scene in which she is alternately attracted to, then repelled from, the old geezer the potion makes her fall for is great comedy. It’s hard to believe she is not a music major. Sara Zeglevski (Aline), Jesse Murillo (Sir Marmaduke Pointdextre), Matt Peckham (Dr. Daly) and Diana Herstein (Mrs. Partlet) were also uniformly strong.

High marks to all for diction; despite the English-y accents, the supertitles were barely needed. The orchestra, led by Yaniv Segal, continued an UMGASS tradition of excellence. At first, some of the ensemble singing was a bit ragged, and the dancing seemed by the numbers, but both improved as the performance went on.

An added bonus: Thanks to this show, I learned the difference between a “filter” and a “philter,” although I am still pondering the meaning of the line “But tush! I am puling.” But that’s Gilbert and Sullivan for you.

Don’t let the fact that “The Sorecerer” doesn’t have the marquee recognition of “Pirates of Penzance” or “Mikado” (coming up in April, by the way) deter you. Once you get past the first 20 minutes, this one easily holds its own with some of the duo’s better-known shows.