Emalina Varlen became a soldier after her parents and village were destroyed in the titan attack. After being saved by the Scouts, she joins the Cadet Corps to become a soldier for the regiment that saved her. There, she meets Jean Kirschtein, and soon they become inseparable, joining as one once they graduate. She enjoys her time in the Scouts, but suffers when she realizes two of her closest friends are the reason for this nightmare, and becomes a titan shifter like them.
Reiner Braun, a soldier for Paradis, but a warrior for Marley. He's stuck on the devil's island, disguising himself as a soldier to search for the coordinate, but also for a suitable devil to become the next titan shifter. During training, he meets Emalina Varlen, and his views on the island devils change as he falls in love with her. Yet, everything changes when Reiner takes Emalina during the Battle of Shiganshina back to Marley, where she must reside forever.
Once in Marley, Emalina and Reiner must suffer through trials and tribulations together to survive. Emalina never abandons her hope that she'll be rescued, but as the days pass, her hope dwindles and vanishes. Living in Marley, she grows accustomed to the enemy, nearly becoming one of them. Her relationship with Reiner alters, and she must question herself: What does the warrior mean to her? Emalina embarks on a journey of love, change, and hardship, where she must decide her fate and determine where she belongs. Does she belong on Paradis with Jean? Or in Marley with Reiner?