Okitegami Kyouko no Konintodoke

The sixth instalment of the Boukyaku Tantei Series.
The forgetful detective Okitegami Kyouko gives her "first" lecture. A dangerous love question is posed towards Kyouko-san while she's on stage leads to a false accusation, and a young man named Kakushidate Yakusuke receives an unexpected proposal...... Will the beautiful forgetful detective be able to stop the cursed marriage?
(Source: Kodansha, translated)