In Macbeth, whom do Macbeth and his wife plan to take the blame for Duncan's murder?

In Lady Macbeth's plan to murder King Duncan--and it was she who worked out all the details--Duncan's grooms (his attendants) were to be blamed for his murder. She would drug their drinks so that they would sleep, and then she would lay out their daggers for Macbeth to use in killing the king. Macbeth was to commit the murder, smear the sleeping grooms with Duncan's blood, and leave the daggers at the scene. Thus it would appear that these men in Duncan's chamber, covered with Duncan's blood, had committed the deed.

Her plan unfolded with two exceptions. Macbeth forgot to leave the daggers behind, so Lady Macbeth had to return them. After Duncan's body was discovered, the king's sons, Malcolm and Donalbain, ran away, fearing reasonably that they, too, were in danger. Because they had fled the scene without explanation, the guilt for Duncan's murder then fell on them. Macbeth and Lady Macbeth certainly didn't argue about this misconception.