Cal Gaiden is not directly connected to other Cal games story-wise, completely abandoning the protagonist Wataru Ishibashi, the storyline concerning ancient Greek gods, and the multi-cultural fantasy setting. Instead, it follows the exploits of Satoru, a young man who its trying to find the love of his life. There are four possible candidates: the initial romantic interest Mari Inoue, the elusive Manako Sakamoto, and two co-workers - Ami and Yōko.
The player can choose to start a specific chapter dedicated to each of these young women (the last two are grouped together). The gameplay largely follows the visual novel format, albeit generally with more options to choose from than it is usually the case with games of that genre. Much of the story is linear, but some decisions may influence the subsequent development of the plot.