As his two-week stint on the secluded island unfolds, Riku maintains the training facility while observing the swimming club’s daily routines alongside their instructor. The discovery of concealed recordings left by the previous janitor leaves him unsettled, prompting him to set the tapes aside without further inspection. Over the following days, however, an unexpected intrigue begins to take hold, challenging his initial sense of disapproval and casting a shadow over the tranquil atmosphere he once enjoyed.