It was Father Sun who was bringing Sun Jie back home. Because of the tension in the Yu house last night, Yu Dong asked Father Sun to take Sun Jie home. The poor mer was already scared enough by the sudden change in the house and when Shen Li started screaming he started to shake like a leave in the storm.
Yu Dong did not want to give unnecessary stress to Sun Jie and the children so she asked Father Sun to take not only Sun Jie but also Yu Mai who did not know anything about childbirth and the pain that came with it.
He was walking back to the Yu house when he ran into Murong Si and paused in his stride.
"You are..?" Since Murong Si did not know who Father Sun was, he could only assume his identity as he was holding hands with Yu Mai, Yu Tong's other cousin and Yu Dong's biological brother.