The earl's coachman goes to collect Miss Thompson, his daughter's new governess, from the stagecoach. He collects a different Miss Thompson, who was expecting to be an old lady's companion. The mistake is not uncovered until the following morning.
The widowed earl is unable to exchange the ladies as the intended governess has now taken the position of companion in place of the young Miss Thompson now in his house.
They have to keep the young Miss Thompson to help them with his tantrum-prone daughter while they go to London to find a replacement governess.
However, could it be that the wrong Miss Thompson turns out to be his Miss Right?