"Happy Heroes League: Lost in Space" is the 17th main storyline installment of the "Happy Heroes League" series. Star Planet's robots become infected with a Trojan program and begin attacking humans. Since this type of Trojan is ancient and can only be developed in the past, Happy Superman travels back in time to Lingguang Star to search for the Peace Code, which can eliminate the Trojan. However, to his surprise, Happy Superman arrives in a time before the Peace Code was successfully developed—a period when conflicts between humans and robots have erupted on a massive scale...