Assault Lily Last Bullet W is a role-playing game set in a near-future Earth where humanity faces extinction due to a mysterious lifeform known as "HUGE." To combat this threat, adolescent girls known as "Lilies" wield a powerful weapon called the "CHARM," showcasing high synchronicity rates. Players experience the adventures of girls from different legions striving to become exceptional Lilies.

The game features a narrative intertwined with the TV anime "Assault Lily Bouquet," focusing on three legions - "Radgrid," "Hervarar," and "Gran Eple," with full voice acting. Memoria cards depict scenes from the girls' lives and battles, offering special stories. Players can combine Memoria to form parties and strategically control Lilies in battles against the HUGE, enhancing their abilities through strengthening both CHARM and Memoria.