A man was stabbed to death in Peterhead after a drug deal "turned ugly", a court has heard.
Elaine Young, 24, and Mark Junor, 34, earlier admitted a reduced charge of culpable homicide after the death of Martyn Stewart last November.
The High Court in Aberdeen was told Young and Junor, who were in a relationship, had wanted to get heroin from the victim but a fight ensued.
Sentence was deferred until next month for background reports.
Advocate depute Gary Allan said: "It is understood that the deceased had raised the price which had been agreed."
Mr Allan said Junor and Mr Stewart came to blows and began to struggle.
Mr Stewart gained the upper hand in the fight but Junor produced a knife.
The court heard the knife was knocked from Junor's hand.
Young picked it up and "struck out" at Mr Stewart, stabbing him in the heart.
The victim collapsed on his couch, where he was later found dead by police.
Mr Allan said: "It is accepted that her blow was not intended to be murderous in quality."
Mr Stewart's older brother David, 42, of Fraserburgh, said: "He was a much-loved son, brother and uncle and he'll be terribly missed by all the family.
"It is tragic he was taken from us when he had his entire life to look forward to."
Grampian Police Det Ch Insp Phil Chapman, who led the enquiry team, said: "This was a tragic and totally unnecessary loss of a young man's life and another example of the dangers of carrying a knife."
He added: "I'd like to thank the people of Peterhead and the Buchan area who provided invaluable assistance during the course of this investigation, which ultimately assisted in identifying and tracing Martyn's killers."
Sentence was deferred on Young and Junor until 24 September at the High Court in Edinburgh.