English Language: can someone please help me with this question?

It was on their first day at the house that Rosie saw the stranger child. Standing at the sink, her hands deep in suds, Rosie was overwhelmed by the tasks that lay ahead of her. Tired after the long drive from London the evening before, she gazed vaguely at the sunlit, overgrown garden where Sam and Cara were playing.

Where is Rosie when she sees the stranger child?

It’s a mistake. She’s at the sink.