Crimson Climax (Japanese: 螢子 - "Hotaruko" / Firefly")^[1] is a hentai genre animation movie released in 2003. It contains thriller, horror and erotica elements.^[2][3]

You can help expand this article with text translated from the corresponding article in Russian. (May 2022) Click [show] for important translation instructions. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Russian Wikipedia article at [[:ru:Hotaruko]]; see its history for attribution. You may also add the template {{Translated|ru|Hotaruko}} to the talk page. For more guidance, see Wikipedia:Translation.

It was first released as a three-part series of films, and later merged and released as an OVA.

After her mother's sudden death, Ryo returns to her island-based family home.^[4] There, she begins to look into her mother's strange past behavior.^[5] Upon meeting her cousin Hotaruko, Ryo is lured into a cult.