AU where Side and Bu Fan run into a mysterious crime to solve while at the new school and Qiang Da/Qiang Wei get involved despite being explicitly told not to steal Bu Fan's thunder
To encourage the children, build school morale, and earn extra income for new computers, Yan Zhang Tai decides the school should hold a week of events (bake sales, carnivals, spelling bees, sports exhibitions, etc). But two days in, the donation box with all the money they’ve earned is stolen! Bu Fan is resolved to solve the case and impress Si De. For her part, Si De has been flirtatious but has not fully committed to him as his girlfriend, as now that they are coworkers, she is concerned that being in a serious relationship would be inappropriate.
Of course, Bu Fan’s plans are complicated by the arrival of Qiang Da & Qiang Wei, who have been invited by Si De to help with charity events (Qiang Da with a math contest between the students, Qing Wei with an antique auction). Of course, everyone has another motive as well: Si De wants to pick Qiang Wei’s brain about her relationship with Bu Fan, Qiang Wei wants advice about how to bring up the topic of marriage to Qiang Da, and Qiang Da has heard about the mystery and wants to solve it. Bu Fan is not thrilled (although he did miss Qiang Da more than he will admit). Even better, one more surprise guest arrives after Qiang Da calls in for backup: Ah Fei!
Solving the mystery includes: Bu Fan repeatedly trying to figure out a clue only for Qiang Da to arrive at the correct conclusion a second before he can, a Scooby Doo-style chase through the hallway, Qiang Wei tackling a presumed perp to the ground like the boss she is, Bu Fan and Qing Da engaging in a wrestling match as one of the charity events (Bu Fan puts up a good fight but obviously loses), Bu Fan & Ah Fei interrogating a series of male students who are all in love with Si De, and a recurring joke where Bu Fan’s fantasies about him & Si De solving the crime are in a 1940′s film noir style.
Ah Fei has a subplot where he falls head over heels with the pretty, soft-spoken aunt of one of the students, and Bu Fan has to bounce a basketball off of his head to get him to focus. Another subplot is that while Qiang Wei (and Si De by extension) is convinced that Qiang Da will never propose marriage on his own, Qiang Da reveals to Bu Fan that he is ready to do so, and is just waiting for the exact right moment. (Of course, miscommunication where they each believe the other is unwilling ensues.) Qiang Da eventually figures it out and proposes, and Qiang Wei excitedly shares the news with Si De, who begins to realize that she wants that same happiness with Bu Fan.
The mystery ends with Qiang Wei & Si De being the ones to solve the case because they worked as a team instead of competitors, which only bothers Qiang Da a little bit and bothers Bu Fan a whole lot. (Ah Fei was just along for the ride so he’s unbothered.) The final event of the week is a teacher auction, and Bu Fan is shocked when Si De outbuys everyone to win the date with him. She tells him that she was touched by his intense desire to solve the mystery and help the school, and that she’s finally ready to take the next step and be his girlfriend. They share a romantic kiss, and everything is lovely
BONUS: Yes, the Ah Fei & Bu Fan handshake makes a reappearance
