The bedroom was dark and she thought it was her occasional lover who slipped into bed.
But the sex felt different. When she turned on the bedroom light, it wasn't her lover but his identical twin.
"Oh my God. Oh my God. Oh my God," she recalled saying as she grabbed her clothes, left the apartment and collapsed in tears on a park bench.
That unsettling end to an autumn party is the subject of a sexual assault case before the Ontario Court of Appeal - in which the usual counterpoint of "he said, she said" is tangled by an odd familial twist.
In hearing the request for a new trial, the appellate court will weigh arguments over whether the woman properly gave her consent or whether her lover's twin duped her. Did the mistaken identity negate her consent?
Many details of the case cannot be reported because there is a publication ban on the woman's identity.
The woman said she was a friend of the brother of the accused - a friendship that included sex. She had moved away from the area but occasionally slept at his flat when she visited.
In the fall of 2006, she dropped by her friend's place while a few people were there for a party. During the evening, she drank three-quarters of a bottle of wine.
She testified that she had never felt at ease around her friend's twin brother. The accused, however, testified that she had flirted with him.
Eventually, the woman felt tired and went to sleep in her friend's bedroom.
The accused, who also had several drinks, said he eventually felt sleepy, too. Because the party was still in progress, his brother directed him to his bedroom.
The accused said the woman initiated the petting and that he asked, "Are you sure?" before they had intercourse.
She said it was the accused who woke her as he began to touch her. She also testified that she called him by his brother's name several times before he penetrated her.
In its factum before the Court of Appeal, the Crown said the accused either acted recklessly or was willfully blind to the consequences of his acts.
He went into his twin's darkened bedroom and, in "a bed she had often shared with his brother," said little as he had sex with a drunk woman, the Crown filing said.
"Anyone, but especially ... the identical twin of the man the woman in bed is having a sexual relationship with, would be cognizant of the obvious risk of being confused for her intimate partner in this situation. To forge ahead anyway is reckless."
After a trial in 2008, an Ontario Superior Court judge found the man guilty and sentenced him to six months in prison. The accused should have done more to make his identity obvious, the judge said. Instead, the man "chose to play it as close to the line as possible in an attempt to ensure that sex, in fact, would take place," the judge said.
The defence said that the judge placed an unreasonably high onus on the man. The accused was not acting in a fraudulent manner, the defence's factum argued. "He believed that the complainant knew who he was," it said.
The bedroom was dark but some light still came through the partly open door, the defence filing said. The defence also said there were noticeable physical differences between the twins, one being slimmer than the other, for example.
In her testimony, the woman said that "little light bulbs" indeed went off in her head as she felt those differences. One brother also had a certain facial distinction, but the woman said it could only be seen when the lights were on.