Featuring characters from NHN's popular app such as Moon, Brown, Connie, James, Jessica, and Sally living happily together in Line Town.

In Cinnamoroll's origin story, a white dog flew down from the skies one day and was discovered by a female Cafe Cinnamon worker. The "I.Cinnamoroll" brand depicts an alternate world that poses a what-if question: What if Cinnamoroll had not met the Cafe Cinnamon worker on that fateful day? The "I" in the title stands for both the English first-person pronoun "I" and the Japanese word "ai" (love), and it represents the brand's theme of taking care of one's own body and mind.

Due to his mother and sister, who both love professional wrestling, Kinjirou Sakamachi developed a resilient body that could take hard punches, aggressive kicks, and even deadly vehicle bumps, in order to survive their various grappling positions and locks. However, he also developed gynophobia, an abnormal fear of women. With just one touch from a girl, his nose bleeds uncontrollably, he sweats excessively, and in rare cases, faints abruptly. His life changes for the worse because of a fated meeting in the restroom. While trying to escape from a girl, he discovers that the most popular student in their school, Subaru Konoe—the butler of the headmaster’s daughter, Kanade Suzutsuki—is actually female! Surprised, Subaru violently assaults Kinjirou, dealing significant damage and knocking him unconscious. When he comes to, he meets Kanade. In exchange for his silence, she promises to help cure his phobia.

After escaping the zombie-infested mainland, Takashi Komuro and the gang find themselves on a remote island off the coast of Tokonosu City. While scavenging around the island for supplies, they encounter a small seaside shack that provides them with clothing and a place to rest for the night. After a day's work of collecting food, they begin to cook what they have gathered. As they wait beside the campfire, a light haze begins to form around them and makes them nauseous. Confirming it to be caused by hydrangeas—a type of poisonous plant that can cause hallucinations—the group attempts to escape from the powerful odor.