Shang Xue, a socially awkward Year 1 student moves into a rented apartment with her rosemary plant, Xiao Ye. She is a fan of mysteries and active user on an online forum that solves mysteries. She meets Junzhe, the most popular boy in university, over a case of a broken window. Shang Xue returns home at night, but someone has been following her... 不善社交的大一新生尚学租下一间小公寓，带着迷迭香“小野”搬入新家。热衷推理的她时常参与网上论坛“问题解决社”的推理社群，网友之一就是现实中的校草俊哲，账号为"Sherrinford"。。。

Junzhe saves Shang Xue from a robbery on her way to school. Shang Xue meets her quirky online friends Gu Mei, Ah Chuan and Jin Xin, and finds herself at home with them. Shangxue keeps receiving ex-tenant Sun Yuze's emails, letters and bills, and imagines her everyday life. She also finds a pendant engraved with "Sherrin". To Shang Xue's horror, someone tries to break in late at night. 上学途中，尚学遭遇抢劫，被俊哲救助。尚学与行径古怪的网友们顾湄、阿传和金鑫见面，找到久违的归属感。尚学浏览孙雨泽的邮箱...

Xue becomes close friends with Gu Mei, Ah Chuan and Jin Xin. She receives a branded dress on her birthday and tries it on, only to realise it is a gift for Yuze. She gets a makeover and wears the dress to places Yuze frequented but runs into Junzhe. Shang Xue receives an SOS call from Gu Mei and rus

Shang Xue celebrates her birthday with her friends. She worries that Yuze is in danger when her neighbour Ms Liu goes missing. She finds a photo of a keychain with "ford" on it on social media and thinks of "Sherrinford" from the mystery forum. Shang Xue and Junzhe attend the press conference for The Missing Body: Part 2. Unbeknownst to them, someone is watching them. 朋友们为尚学庆生，不亦乐乎。邻居刘小姐失踪，令尚学担心孙雨泽也身处险境。她在社交媒体上找到一张照片，上面展示着“ford”的钥匙圈。。。

Shang Xue and Junzhe are caught in the rain and share a sweet moment. Junzhe is shocked to discover Shang Xue living in Yuze's block when he sends her home. Junzhe keeps a distance from Shang Xue, but both miss each other in secret. One day, Junzhe turns up at Strangers Caf after Shang Xue visits it. Meanwhile, she is in danger and trapped on a balcony. 俊哲和尚学被困在雨中，气氛暧昧。俊哲送尚学回家，却震惊发现尚学和孙雨泽住在同一栋大楼。尚学和俊哲数日没有联络，各自回到自己的生活，心情却犹如失恋。这天...

Belle ties Shang Xue up and nearly pushes her off the balcony. Junzhe arrives in time to save Shang Xue and takes her to the archery range to take her mind off things. Sparks fly between them but Junzhe hesitates. Jin Xin aids Shang Xue's search for Yuze with a plant sensor. Junzhe gathers his courage and asks Shang Xue out. He agrees to take her to his secret garden next time. Belle因误会而报复尚学，把她绑在天台栏杆边还差点把她推下。俊哲赶来，为尚学解围，并带她去射箭练习场分散她的注意力。两人互动暧昧...

Jin Xin suspects Junzhe is involved in Yuze's disappearance but nobody believes him. Shang Xue and Junzhe have a lovely date at the garden. However, Shang Xue falls out with Junzhe over Yuze. Gu Mei and Shang Xue investigate more about Yuze and suspect Eddy is behind her disappearance. Junzhe brings Xue to a fireflies' park and sparks fly as romance fills the air. 金鑫怀疑俊哲与孙雨泽的失踪有关，却没人相信。尚学与俊哲在花园度过美好时光，俊哲还穿汉服表达歉意。顾湄确定俊哲对尚学有意思，尚学却因孙雨泽而和俊哲起争执。。。

Junzhe sees Shang Xue flirting with Eddy and thinks that she is cheating on him like Yuze did. Shang Xue finds a snake at home and turns to the security guard Mr Wu for help when Junzhe doesn't answer her calls. Seeing how upset Shang Xue is, Ah Chuan and Gu Mei try to clear the air with Junzhe but fail. 俊哲追踪尚学却目睹她勾引Eddy的一幕，误会她和孙雨泽一样背叛他。俊哲伤心绝望，与尚学切割。尚学发现家中有蛇，打给俊哲求助却无人接听，只能依赖保安老吴。在Dione的追问下，尚学透露俊哲喜欢推理，却反而加深俊哲对尚学的误会。阿传和顾湄心疼尚学，找俊哲解释，俊哲却不予理会。

Junzhe and Shang Xue make up in the fireflies' garden. They find Yuze's uncle but disagree over why Yuze is missing. Shang Xue gets a video call from Yuze, proving that she is alive. Junzhe recalls his childhood and worries he may also be bipolar. Yuze's uncle dies mysteriously and Shang Xue suspects the call with Yuze was a deepfake video. Someone calls her from her supposedly-empty house. 俊哲和尚学在萤火虫花园和好，甜蜜亲吻。他们找到孙雨泽的舅舅，却对孙雨泽的失踪持相反意见。。

Shang Xue moves into Junzhe's place. She figures out he is Sherrinford and pieces the clues together, including the suspicious wall in her house. Junzhe decides to overcome his fears and move on with Shang Xue, who now mistrusts him. When Shang Xue decides to uncover the truth, she is suddenly attacked by the murderer. The murderer reveals his identity and intends to silence Shang Xue. 金鑫、顾湄和阿传陪尚学回家，没察觉任何异样。尚学暂住俊哲家，也因此猜到俊哲就是“Sherrinford”。。。