What happens if an old machine shrinks the big ego of Lum the Invader resulting her to fully apologize & fix all her past mess ? --- 1 month is all needed for her to 'fix' everything which includes the ' Memory Alternation ' machine she made to change the memories of her to someone else in Ataru's brain . --- Prim , Prince of Underground's wife volunteered to take care of Ataru for 2 weeks until the process of alteration complete . Meanwhile things have gotten messy in Planet Oniboshi after the sudden change of Prince which lead to the 2nd half of the story . --- Lum's intense emotion after leaving for her darling's sake attracted a huge event caused by the title " the Invader " .