With the divorce of his parents, seven-year-old Koyomi Hidaka makes the important decision to live with his father. As a researcher at the Japanese Institute of Virtual Science, Koyomi's father is involved in the investigation of the phenomenon of parallel worlds. Through his father's job, the young boy meets Shiori Satou, the daughter of another divorced researcher. Soon becoming friends, the two spend much of their childhood together. As Koyomi and Shiori grow closer together over the years, the two intend to marry in the future. However, their plan comes to a halt when their parents decide to marry each other. Now fated to being step-siblings, the two friends refuse to accept their new reality. Using their parents' research, Koyomi and Shiori escape to a parallel world to start their lives anew together, only to face repercussions that will put the very futures they strove for in danger.

In the aftermath of Amagami SS, high school student Junichi Tachibana continues his relationships with the girls at his school. Amagami SS+ Plus offers a glimpse into what happened after the resolution of each girl's individual story. New events begin to take place between each of the girls and Junichi. Tsukasa Ayatsuji, the class representative, runs for student council president; Rihoko Sakurai, who has taken over the Tea Club with Junichi, still wants to confess her feelings to him; Ai Nanasaki questions the future of her relationship with Junichi when he leaves for college; Kaoru Tanamachi wonders if her relationship with Junichi will ever go any further; Sae Nakata and Junichi deal with classmates who still can't believe that someone so cute is his girlfriend; and Haruka Morishima wants to take their relationship to the next level and get married.

The story follows the strongest king in history, Grey. Although he possesses unparalleled power, wealth, and fame, there is no one who stands by his side…and he trusts no one. One day, Grey suddenly meets his death and is reincarnated as a powerless infant named Arthur in a world of magic. Surrounded by a loving family and companions, Arthur starts to experience joys in this new life that he never knew in his previous one. However, during a journey, his family is attacked by bandits... Thus begins his second life, filled with love and adventure! (Source: Official site)

In a small church atop a hill, Pastor Lawrence looks after Saint Cecilia. Her presence is a beacon of hope for the villagers, as her mysterious powers protect them from the weakness of their minds and outside evils. While she appears dignified in front of the villagers, Cecilia allows her lazy side to show when alone with the pastor. Although Cecilia is the guardian of the people, Lawrence is determined to shield her from harm. Unbeknownst to Lawrence, Cecilia harbors a huge crush on him. She accompanies him on his shopping trips and provides him with divine protection every day. Despite Lawrence remaining oblivious to her true feelings, Cecilia continues to shower him with obvious displays of affection as the bond between them grows.