Adventure Comics #418

Nasthalthia Luthor hires detective Jonny Double to track Linda Danvers, suspecting her to be Supergirl. Double and Linda encounter the Dragon Tong in Chinatown, where Supergirl thwarts their plot. They uncover a connection to Dr. Tzin-Tzin, leading to a showdown. Double refuses Nasthalthia's manipulative scheme and questions Linda's true identity, but remains skeptical.