Chelsea McCarthy’s house burned down when she was 24 years old. She had paid off her credit card debt earlier that month, mailed her rent payment on her Christiantown home that morning, and had no money in the bank. At the end of the day all she was left with was some jewelry, perfume, her birth certificate (somehow it survived the fire), the clothes she had on and one of her two cats.

So much for having her life sorted out.

The Island-grown actor had just resolved, once and for all she thought, her uncertainty about pursuing a life in theatre. She had long been interested in theatre; her mother, Taffy McCarthy, is a Vineyard actor, director and musician. But Chelsea had some reservations. To put those to rest, she had just completed a monthlong intensive actor training session at Shakespeare and Company in Lenox.

“I remember walking in the door and going, ‘At the end of this month I’ll know if I am ever going to be an actor again; if I go through this monthlong period and at the end of it I go like, ‘I can’t do this, it’s not for me,’ then I’ll know. And what happened is I came out on the last day and I thought, ‘I may not be any good, but I’m an actor,’” she said.

An actor without a house. She moved in with her mother and entered a period of reflection. “My mom said, ‘Well, what are you going to do now?’ and I was like, ‘I don’t know, I have nothing,’ and she was like, ‘Yeah, but you have nothing; you have nothing to tie you down now, you’re starting out fresh. So what are you going to do now?’”

Chelsea McCarthy pursued drama with a passion. Now the actor is staging her first full production as a director for the Vineyard Playhouse: A Comedy of Errors, this year’s Shakespeare in the Amphitheatre.

Ms. McCarthy has performed in every summer Shakespeare for the past seven years. She has been Celia in As You Like It, the nurse in Romeo and Juliet, and, her favorite, Kate in The Taming of the Shrew.

She also has had roles in other mainstage shows at Vineyard Playhouse, where she is also the resident costume designer. She is costuming her own show with the help of her sister, Paige McCarthy.

It’s all a natural progression. For the past three Vineyard winters, Ms. McCarthy and her friend, the Island actor, director and writer Nicole Galland, have produced and staged readings of the Bard’s works in the series Shakespeare for the Masses. Their motto is “quick, painless and free.”

They cut Shakespeare plays down to about one hour, writing narration to fill in plot points or to add jokes to their not-at-all sacrosanct interpretation of the plays. They conceive it with plenty of movement and fight choreography. Actors, dressed all in black, literally wear different hats to denote the different characters, sometimes adding sight gags to the jokes in the narration. The series has gathered a devoted following of audience members and actors who participate regularly.

Ms. McCarthy and Ms. Galland share the responsibilities of cutting the scripts and directing the actors. They assemble a cast that comes from near and far and rehearses in a period of two days.

Now the debut director and her cast of 17 are in the thick of a two-week rehearsal period for A Comedy of Errors.

“[Shakespeare for the Masses] really helped. It’s like, ‘If I needed to, I could put this on tonight,’” Ms. McCarthy said, laughing, knowing that many directors would be getting anxious a week before their opening.

Vineyard Playhouse artistic director MJ Bruder Munafo said it was Shakespeare for the Masses that inspired her to invite Ms. McCarthy to direct the summer Shakespeare. “She directed some of their ‘lively staged readings,’” Ms. Bruder Munafo wrote in an e-mail recently, “and I thought, ‘Chelsea is a good director, too!’ I decided that I would like her to direct her first full show for the playhouse ... it was easy to make the decision to ask her to direct this summer’s production at the amphitheatre.”

Ms. McCarthy calls the amphitheatre “my favorite place in the world.” Located in a woodland grove near the Tashmoo Overlook, it fills with people spreading blankets on the benches and nibbling picnics as the performances begin at 5 p.m. each night as the heat of the day wears off.

“It’s my favorite place to do theatre,” she adds. “I love that space. I love being outside. I love the bugs and the dirt.

“I love having the audience so close and not be blocked [from the actors] by, you know, the wall of black from the lights into the audience. Because as an actor, I really like to tell people the stories. I like to look into the audience — not too long because sometimes it makes people uncomfortable and they can’t meet your eye — but there’s something in the amphitheatre, because you’re in broad daylight and they’re so close to you, that you can involve them in the story, get them on your side, or turn them against you,” she said.

Ms. McCarthy worked with her actors last Saturday in their first full-cast rehearsal. The sun was out and it was warm on the grassy stage. As she worked, Ms. McCarthy’s fight director, John Robichau, marvelled: “She sees it.

“It’s like reading the matrix,” Mr. Robichau said, watching her coach the actor. “I love Chelsea’s directing style. She becomes the voice of your unconscious,”

In a phone interview recently, Nicole Galland remarked on how Ms. McCarthy has developed as a director through doing the Shakespeare readings over the past three years.

“The main thing that I’ve seen is her confidence level working with actors. She has always been a very confident and very strong presence, but her being very clear and very decisive,” she said.

Ms. McCarthy also has developed expertise in trimming Shakespeare’s plays down to a manageable length while retaining the essence of the story and the characters. Usually she follows her gut instinct when cutting lines out of the scripts, but for this production she took pains to make the script exactly the way she wanted it, she said.

“Doing all of that really intensive work on [the script] means that when people ask me what a certain line means, or when I feel like maybe the actor doesn’t know what a certain line means, I know it all,” Ms. McCarthy said.

The plot of A Comedy of Errors centers on two sets of identical twins who wind up in the city of Ephesus, and everyone around them confuses one for the other.

During last Saturday’s rehearsal, she was working with Adam Petkus, playing Antipholus of Syracuse, and Dylan Schwartz-Wallach, playing Dromio of Syracuse. In one scene, a courtesan enters and asks Antipholus for a golden chain he had promised her. In fact, it was his identical twin, Antipholus of Ephesus, who had promised that chain. The courtesan invites Antipholus of Syracuse to dinner, viewing him as a potential ‘client’ and hoping to get her promised chain.

However, these two characters have never met her.

Dromio cautions Antipholus not to go, saying: “Marry, he must have a long spoon that must eat with the devil.”

Ms. McCarthy stopped the actors, who were not fully understanding the line.

“She’s a whore,” she explained, “and the devil needs a long spoon to eat with her.”

The sexual innuendo now clear, the actors tried it again.

“More long spoon,” Ms. McCarthy said.

They cracked up laughing in their next attempt as the metaphor sank in.

“Long spoon,” Ms. McCarthy repeated, keeping the actors focused on the crux of the joke.

The boys delivered the lines to her satisfaction and soon exited the scene, running away from the imposing woman, whom they think might be a witch. But they ran off without a clear intention, so Ms. McCarthy called them back.

“Wait, come back. There must be a reason they run off,” she said.

This time she works with May Oskan, the actor playing the courtesan. They decide this courtesan may be really tough, and might even carry a knife. The context immediately clicks with Ms. Oskan.

“I will shank you,” she chuckles to the boys, imitating the attitude that she now will carry into the scene.

They do the scene one more time, and this time the courtesan is more serious and imposing, and the boys run away with more genuine fear.

Ms. McCarthy nods her head and they move on to the next scene.

A Comedy of Errors opens Wednesday, July 20, and runs through August 14. The show starts at 5 p.m., Wednesday through Sunday, at the Tisbury Amphitheatre. Tickets are $15 for adults, $10 for ages 18 and under.