Mizuki Mochizuki is a seventeen-year-old high school student and the central figure of Last Quarter. At the start of the story, she is weighed down by personal troubles, including her father's remarriage and the betrayal of her boyfriend Tomoki, who cheated on her with her best friend Aya. Despite this, she often smiles at the sadness in her life, which only makes her feel heavier inside. Her motivation is a desire to escape from her painful reality, and she finds a gateway in Adam, a British musician she meets one night under the full moon. She quickly falls in love with him and begins avoiding her family and friends to secretly spend time with him in an abandoned mansion. Her role in the story is that of a protagonist whose yearning for freedom leads her to make a fateful decision: when Adam says he must leave by sunrise, she decides to run away from home to follow him, but while crossing a street in Shibuya she is hit by a car and falls into a coma. After the accident, her spirit becomes trapped in the abandoned mansion, having lost most of her memories except for those involving Adam. She is discovered there by a young girl named Hotaru Shiraishi, who is the only one able to see her. Hotaru and her classmates nickname the spirit Eve and work to help her recover her memories, eventually identifying her as Mizuki. As the story progresses, it is revealed that Mizuki's body is still alive in a hospital, but her spirit has been possessed by the ghost of Sayaka Kamijo, Adams deceased girlfriend. The children realize that Sayaka is using Mizuki's form to find Adam, and that the only way to free Mizuki is to give Sayaka closure by revealing that Adam died in 1979, long before Mizuki was born. When Hotaru tells Eve the truth, Eve vanishes and reappears at the site of Mizuki's accident, and Mizuki's physical condition deteriorates. Hotaru chases after Eve and convinces her that she is loved by her family and friends, giving her the will to live. Eve then disappears, and Mizuki wakes from her coma after Adam leads her out of her dreams. After awakening, Mizuki returns to her normal life with no recollection of the supernatural events that occurred. Her key relationships include her love for Adam, who is a wandering spirit that genuinely falls in love with her during their time together; her connection to Hotaru, who acts as her bridge to the living world; and her complicated past with her ex-boyfriend Tomoki. Her development moves from a girl seeking escape from sorrow to someone who ultimately chooses to live, supported by the care of those around her. She does not possess overt supernatural abilities, but her spirit is able to interact with the living world while in a coma, and she is the vessel through which Sayakas ghost seeks resolution.