It is summer of 2009. In a southern Chinese town, it is stiflingly hot before the arrival of a rainstorm.
Li Senlin is bored and stuck doing homework. Auntie Qiu, a boatwoman who hasn’t shown up for years, suddenly makes a visit, and recounts the tale of a strange encounter on an abandoned island.
Li Senlin loses her turtle while her father is away on a business trip. There’s another “Senlin” that keeps on being mentioned by her parents. She faintly suspects that Auntie Qiu is actually her biological mother.
The summer rain pours down as memory and reality interweave into one another. The water of the Great Canal dampens each individual that roams along it, and a red flag flaps still at the stern.