The secret ingredient is a slightly sweet ulterior motive summary: A slow-paced love story about a popular barista and a cross-dresser streamer, two people with a secret. I finally meet you, you're my favorite! Coffee shop worker Hirayama Shun is so handsome that customers praise him every day. However, he is fed up with being treated with contempt by a regular customer, Mao Nakadai. Then, one day, he meets MAO, a beautiful streamer girl on a video site and falls in love at first sight. He is actually an idol otaku, and when he watches her previous videos, he discovers that he is a cross-dressing guy. Although he is supposed to be straight, Shun is perplexed by his crush on MAO, even though he knows she is the same sex as him. He then discovers that MAO has similar characteristics to Nakadai, the regular customer...!