Denpa teki na Kanojo (電波的な彼女, lit. "The Radio Wave-Like Girlfriend", translated as Electromagnetic Girlfriend) is a light novel series by Kentarō Katayama, with illustrations by Yamato Yamamoto. In 2009, a two-episode OVA adaptation was exclusively bundled with the pre-order editions of Kure-nai DVD volumes 3 and 4. Under the title Denpa Biyori (電波日和, lit. "Radio Wave Weather"), the first story in the series won an honorable mention at the Super Dash Novel Rookie of the Year Awards in 2003. Three novels were published between 2004 and 2005 with an additional short piece of writing being included with the OVA.
Juuzawa Juu is a delinquent high school boy who just wants to be left alone. One day, he is approached by Ochibana Ame, who claims that she knew him in a previous life, and now wants to serve him as his "knight". At first Juu wants nothing to do with Ame, but after a classmate is murdered, he accepts her help as he looks for the killer.