After dying during a high-risk mission against an underground mafia, Ali, Kim, and Alicia are reincarnated in a medieval world of assassins, nobility, and dark conspiracies. They awaken in the Tuatha Dé and Viekone families, gaining new identities but retaining their past memories. Ali Tuatha Dé, now Lugh's cousin, trains in both modern and magical assassination techniques. Kim becomes Kimberly Lestanian, a skilled alchemist and warrior, partnering with Maha and Tarte. Alicia is reborn as Alicia Viekone, cousin of Dia Viekone, involved in noble politics. However, corruption and crime plague this world as well. Former enemies such as Dr. Aaron, Viktor, Dos, and Jenny (Cinco) resurface, now engaged in illegal trades such as drug manufacturing and human trafficking. Ali, Kim, and Alicia join forces with Lugh and his allies to dismantle this new underworld. But a deeper mystery unfolds-before their reincarnation, the trio was assassinated by a powerful villain using a microbug, whose identity remains unknown. Their new mission is not only to eliminate this world's mafia but also to uncover the truth behind their past deaths.

In this fan-made crossover, Ali and Alicia from M.A.T.A. team up with Kazuya and the rental girlfriends (Mizuhara, Mami, Ruka, and Sumi) from Rent-a-Girlfriend. While tracking the villain Uno in Japan, Ali and Alicia protect the rental girlfriends from Uno's minions, Dos and Trez. Ali's IRIS override mode gives him increased strength but causes immense pain, complicating the mission. As the plot unfolds, Uno seeks to harness the hidden power connected to the rental girlfriends. With betrayal from Jenny, a secret ally of Uno, Ali and Alicia must overcome overwhelming odds to defeat Uno and save the city, forging a strong bond with their new allies.