Namco X Capcom is an action tactical role-playing video game developed by and featuring characters from games produced by companies Namco and Capcom. The game centres on two original characters created for it, Reiji Arisu and Xiaomu. The two of them work for a special unit called Shinra, which is tasked with investigating spirits and other otherworldly disturbances. The game is a hybrid of action and tactical role-playing games. Movement is done on a square grid with turns being determined by figuring out which character has the highest AP. On the player's turn, he or she can move his character into position and choose to attack an enemy.

The game centers around two original characters; Arisu Reiji and Xiaomu, agents of a secret organization known as "Shinra", who deals with supernatural occurrences. Before the game's story, Shinra stopped a plan from the "Ouma" organization to create "fluctuations" to open up portals between worlds, albeit at the cost of Reiji's father life. Ten years later, Reiji and Xiaomu are investigating new fluctuations happening in Shibuya, Tokyo; and soon discover that characters and locations from different worlds and times are converging together, and "Ouma" agent Saya, related to the death of Reiji's father, is involved.