Once Over Lightly

A SLIGHT ERROR, and the same occurred in this tale about a chap who had an ailing mother-in-law in a distant city. Every Friday night, he'd drive his wife to the bus terminal and see her off on a weekend visit with her mother. He'd remain there, and about half an hour later, another bus would arrive, bringing his sister from a neighboring town. She'd spend the next two days looking after him and his children. On Sunday nights, the process would be reversed.