Just a few short blocks from Emerson at the Boston Center for the Arts in the South End, playwright David Harrower’s iBlackbird/i forces itself upon the audience with its disturbing, racy plot.

The SpeakEasy production, directed by David Gammons, begins as two characters engage in an incredibly uncomfortable confrontation. Almost instantly, their relationship is revealed: at the age of 12, Una (Marianna Bassham) was involved in a sexual encounter with 40-year-old Ray (Bates Wilder).

After serving three years in prison for his crime, Ray has apparently tried to make some semblance of his life, with a new job and a new healthy relationship. Now, Una has come to confront Ray about the details of their affair, clearly traumatized by the events of the past.

As the pieces of their relationship are presented throughout the show, it becomes increasingly evident that Una and Ray’s sexual history existed beyond Ray’s attraction to Una. At 12, Una was a Lolita of sorts, seducing Ray into an illegal relationship that eventually proved to be detrimental to both of their lives.

Though the story is about as chipper as a funeral, I found myself oddly drawn to this production. Having neither preconceived notions nor the foggiest idea of the show’s premise, I was shocked by how abrasive and utterly uncomfortable it was.

I feel guilty admitting that I enjoyed iBlackbird/i because in essence I am saying that I enjoyed watching two of the most miserable, unhappy people fight, argue and let their lives spiral out of control. Yet, it was entirely captivating and intriguing.

The acting and the writing are so fresh and remarkably realistic (at times you might believe that the show was completely improvised) that the upsetting plot is less likely to turn audiences away; rather, it entices you to empathize honestly with the characters and their truly horrific lives.

Bassham is outstanding as Una. She commands attention with her erratic movements and devilish charm. Watching her belittle Ray and coax him into admitting his feelings toward her is beautiful in its portrayal yet heart-wrenching as more details of their sordid past are revealed. Bassham is able to make you forget you are watching an actress portraying a character; she really is a furious woman whose torment becomes our own.

Similarly, Wilder gives a phenomenal performance as Ray. Watching the transition of power between him and Una is stunning and his reactions to his loss of control in the face of Una make it difficult to associate him as the play’s only villain.

Harower’s writing is remarkably realistic and unabashedly honest in its depiction of the two main characters. Despite their unlikable personalities, the audience cannot help but appreciate the character depth and the true destruction and break-down of the main player’s emotions. Both Una and Ray deliver lines that are so natural that nothing about their interactions comes across as contrived.

Despite its dark tone and uncomfortable plot, iBlackbird/i strives to make the audience feel as much as the characters emote onstage. In nearly every way, the BCA’s production succeeds. With its intelligently conceived script and perfectly executed delivery, this grim and downbeat play is an event not to be missed.