The Arrogant Master's Little Junior Sister Is Three and a Half

Ming Hanyan transmigrated into a book. The good news was that she'd become the senior sister of the female lead, a mighty heroine. As long as she stayed close to the powerful ones, she'd at least have a guaranteed place in the future. The bad news was... Her mighty junior sister was only three and a half years old, and a child she had to raise. Notes: None for now. I'll add some when I think of them.