Kogoro, Ran, and Conan are invited to comedian Asako Fujimori's birthday party, even though Kogoro failed to find her stalker. When they arrive, they discover that Fujimori has stabbed a man in a zombie mask. They presume that the zombie is Fujimori's stalker, but discover that it is Jiro Imaoka, Fujimori's partner in her comedic career.
While investigating, Kogoro deduces that Imaoka wanted to scare Fujimori to worsen her heart condition and force her to retire as his comedic partner and concludes the murder to be self defense. Conan's investigation leads him to believe Fujimori made up the stalker in order to murder Imaoka. He tranquilizes Kogoro and reveals that Fujimori and Imaoka met at a nearby park, evidenced by the cockleburs found on them. Fujimori then pretended to lose her key and faked a heart attack forcing Imaoka to enter through the apartment's balcony to retrieve her heart medication. Fujimori, enters her apartment before Imaoka does and murders him. Fujimori confesses and reveals that she murdered Imaoka after hearing him plan to end Fujimori's career and start a new life. Soon after, a package arrives from Imaoka, revealing he wanted to end their career in order to settle down in marriage.
