After wetting her diaper, Sosha lies about it to Nikko. When Nikko discovers that Sosha lied, she spanks Sosha as punishment.
The video starts with Sosha only wearing a diaper, which Nikko suspects is wet. However, when Nikko asks Sosha if she is wet, Sosha insists that she isn’t. Not entirely believing Sosha, Nikko checks the diaper to discover that her suspicions are true, Sosha has indeed peed in her diaper.
Since Sosha lied about wetting her diaper, Nikko has decided that she needs to be punished. Nikko takes the wet diaper off Sosha, makes Sosha get into a proper spanking position, and proceeds to spank her for wetting her diaper and lying about it.