POULSBO — When the final performance of “The Sound of Music” ended at North Kitsap High School March 9, it lowered the curtain on one of the most successful stage careers in the school’s history: that of Sylvie Davidson.

Davidson has played a minor Shakespeare character marked for death, a high-school student gunned down by a classmate, a saucy maid in a centuries-old classic, a female Shakespeare character who masquerades as a man, a tough-minded tutor to a wild blind girl, and a governess threatened by Nazis.

Classmates, teachers, and audience members have long been impressed by Davidson’s ability to occupy a character. Of Davidson’s performance as Annie Sullivan, the tutor who taught Helen Keller, drama advisor Sharon Ferguson said: “It had so much maturity. When you see it, you believe it’s real life happening in front of you. That doesn’t happen very often.”

Davidson’s first play at NKHS was “Rosencrantz and Guildenstern Are Dead,” which was staged in her sophomore year; Davidson played Guildenstern, a minor character in Shakespeare’s “Hamlet” that wanders in and out of the play along with companion Rosencrantz.

The Tom Stoppard play is a challenge for an actor or actress of any experience level. It’s a witty, bullet-fast ride where the two leads cannot depend on vast sets, sugary songs, or even other actors. One scene, where the two questions volley questions at each other, is 42 pages long, and one stray word or missed question could wreck the play.

But for Davidson, the play was more than a technical feat. It was one of the first plays that demonstrated to her the power she had in interpreting a character, and the power, in turn, a character had over her own life.

The play ends with Davidson’s character, Guildenstern, alone onstage. He has just learned of his own inevitable death.

The character utters the line, “Now you see me, now you —”

Then the stage goes dark. The play is over.

While the buzzing theater would grow quiet, and the audience departed, Davidson would remain silent and somber, sometimes sitting on the edge of the stage and watching the crowd disappear.

“To have that surge of emotion, then just have it end …” Davidson says. “Sometimes there would be cast parties afterwards, or we would go to Shari’s. But Tito (who played Rosencrantz) and I didn’t want to leave the auditorium. It didn’t seem over.”

Davidson had caught the acting bug long before her sophomore year. When she and a few neighbors were children, they would perform plays in a grandfather’s yard and charge $2 for admission. Years later Davidson worked with the Seattle Children’s Theater for a summer, and on the ferry ride back would chant Shakespeare lines to herself over and over.

Soon Davidson was on stage at the high school, telling complex, compelling stories to auditoriums packed with people.

Drama requires much of the actors and actresses who perform it. They are mechanics who pull apart a role and re-construct it; they are psychologists who analyze their characters from the way they move to the way they think; and they are inventors, constantly recasting roles, which is why every Hamlet who walks onto a stage is being born for the first time.

Jonathan Christensen, who has acted in several plays with Davidson including “Tartuffe,” “The Miracle Worker,” and “The Sound of Music,” said Davidson excels in every role; he believes her experience and work ethic made her the actress she is.

“She tries a lot of things out,” said Christensen. “She’ll do a scene, then tweak it and tweak it until it feels right. It’s playing with your character. If you play with it enough, that’s when you start inventing a character.”

Davidson works on characters in different ways. Sometimes she will go through rehearsals until moments, tics, or personality traits slide into place; other times she has done research, like when she played Annie Sullivan and read Helen Keller’s book on her former tutor to gain insight into Sullivan’s childhood.

From that book and others, Davidson learned that Sullivan’s mother had died, and that her father had left the family; that her brother, whom she had protected, had died while the two were kept in an insane asylum because there was nowhere else to put them; and although not all of that information was in the play, Davidson felt it added depth to the role.

“She was guarded about relationships, especially technical ones, before she went to the Kellers,” Davidson said of Sullivan.

Davidson’s research leaked into the play, especially in a scene when Sullivan confronts Helen’s father (played by Christensen). The scene escalates until Sullivan snaps: “I don’t even love her! She’s not my child!”

Davidson twisted the line this way and that in rehearsals, until she realized that Sullivan began the sentence angry and ended it realizing that she did indeed love Helen Keller.

“That role felt more genuine because Could see why she said things that she said, or did things that she did,” Davidson said.

Davidson’s work as an actress requires as much muscle as it does mind. For their roles in “The Miracle Worker,” Davidson and Erika Nelson, who played Helen Keller, performed a brutal fight scene that left both actresses with bruises to the point where Nelson wore knee pads to perform. Davidson had to teach herself to dance and sing at the same time for “The Sound of Music,” no easy feat when a small physical move would make her voice leap. And for “Rosencrantz and Guildenstern,” Davidson, who played a male role, had to learn to walk and talk like a man.

That role in particular stayed with her: while attending Tolo that year, Davidson was surprised in one picture with her date that showed her standing with feet spread apart at a manly distance (“Well … it was comfortable,” she explained); she moved the feet together for the next shot.

Whether it’s Guildenstern’s walk or the flippant wit of Doreen, the maid in Moliére’s “Tartuffe,” Davidson said pieces of each role stick to her both on stage and off.

In “The Sound of Music,” Davidson cried real tears when the mother abbess sings “Climb Every Mountain.” The cast of “Bang Bang You’re Dead,” a play about school shootings, shed real tears, as did the audience.

One afternoon, in rehearsal for “The Sound of Music,” the boy who played one of Davidson’s children tripped on a prop backstage and hurt his ankle. Before she knew it Davidson had rushed to the child’s aid, picked him up, and spent several minutes soothing him as the pain subsided. Classmates joked that Davidson’s maternal instinct was drawn out by her role as Maria; Davidson’s not so sure it isn’t true.

“I’ve always felt the emotion of my characters,” said Davidson.

Whenever “Rosencrantz and Guildenstern” ended, Davidson said, it was Guildenstern the character who was left alone onstage. But she could feel her own heart pounding every time.