Senior, Your Little Dog Is Misbehaving tells the story of freshman Lin Fan, who accidentally crosses paths with the aloof campus belle Zhao Qingling due to a luggage mix-up. A book of social death diary leads the two to sign a co-habitation service contract, ranging from mutual leverage, bickering, and ambiguous tension to joining hands to face campus public opinion and a wealthy family crisis. As the Zhao Group is hunted down by the Huang family, Lin Fan gradually reveals his hidden information security and business judgment abilities, and Zhao Qingling also grows from a willful young lady into an independent group heir. In successive battles side by side, the two confirm their true hearts, finally shattering the Huang family's conspiracy, tearing up the contract, and completing a sweet counterattack from master and little dog to lovers and husband and wife through voluntary companionship.