“Bell, Book and Candle,” by John Van Druten, is the type of light entertainment Acadia Repertory Theatre in Somesville does best. There’s that appealing mix of humor, magic and love that makes this play about modern sorcery an enchanting way to spend an evening.

The plot concerns Gillian Holroyd, a potently gifted and beautiful witch who has become bored with her broomstick and intrigued by the relative normalcy of humans. She becomes interested in her upstairs neighbor, Shepherd Henderson, and decides to cast a spell on him. Try as he might, he cannot resist her powers, of course, and he falls in love.

Trouble rounds the corner when Gillian finds herself in love, too. Witches, it turns out, are not allowed to fall in love. They can have dalliances by the score, but to actually fall in love jeopardizes their special powers. And here’s where the action picks up its punch.

Gillian longs to be conventional. Her wacky witchy-poo aunt wants her to be happy. Her warlock brother wants her to have fun. A rival witch taunts her with counter-spells. A nutty writer, who is drawn into the plot by witchcraft, wants a good story. And Shepherd is trying to understand the strangeness of the people and events that have mysteriously and suddenly come into his life.

Veteran guest director Wayne Loui, along with stage designer Ken Stack and costumer Rae Johnson, make this a sparkling show to watch.

As is often the case in this type of frothy romance, the supporting cast gets a chance to really let go with some zany bits while the leads are stuck with furthering the love story. Supporting actor Siobhan O’Neill is completely and wildly amusing as the upstairs aunt who glitters with every step she takes. O’Neill has a blast with high-pitched squeals and full-face pouts, and it’s simply a hoot to watch her go at it with such controlled zest. Any more of her tricks would be too much, but she seems to know just exactly when to cut the nonsense. And it works.

Alan Gallant, as Gillian’s brother, and Michael Sears, as the writer Sidney Redlitch, are also entertaining in their character work. Gallant is, at times, over-choreographed in his facial expressions, and Sears can be so caught up in his gruff goofiness that he sacrifices vocal clarity. But by and large they are both quite funny.

Kathleen Lake, as Gillian, combines eeriness, sophistication and vulnerability to create a character that is sympathetic and bewitching. She’s at home onstage, and her elegance and simplicity are much appreciated.

But for all the energy and fun that’s going on under the lights, the show suffers from the “one bad apple” syndrome. While most of the cast is busy acting in a romantic comedy about love potions, mystical black cats and fiery incantations, actor Daniel Vespa, as Shepherd, is aloofly performing in his own private drama. His slow, pensive, internalized approach to acting simply does not fit this piece. Shepherd’s lines in the script are comic, but Vespa manages to turn them into existential drivel.

It’s too bad, too, because otherwise, this show is a charm.

“Bell, Book and Candle” will be performed 8:15 p.m. Tuesday-Sunday through July 23 and 2 p.m. July 23 at Acadia Repertory Theatre in Somesville. For information, call 244-7260.