Into the Water:

A single mother turns up dead at the bottom of the river that runs through town. Earlier in the summer, a vulnerable teenage girl met the same fate. They are not the first women lost to these dark waters, but their deaths disturb the river and its history, dredging up secrets long submerged.Left behind is a lonely fifteen-year-old girl. Parentless and friendless, she now finds herself in the care of her mother's sister, a fearful stranger who has been dragged back to the place she deliberately ran from—a place to which she vowed she'd never return.

The Girl on the Train:

Rachel catches the same commuter train every morning. She knows it will wait at the same signal each time, overlooking a row of back gardens. She's even started to feel like she knows the people who live in one of the houses. 'Jess and Jason', she calls them. Their life - as she sees it - is perfect. If only Rachel could be that happy.And then she sees something shocking. It's only a minute until the train moves on, but it's enough.