The Animated Series, Joker plants a bomb in Gotham City in an attempt to decimate the area with a single explosion. This causes Batman and Commissioner Gordon to turn to an incarcerated Harley Quinn, offering her a full pardon in exchange for helping them track down the weapon. Upon finding the bomb, they realize that Gotham's madman has a biplane ready to escape the city's demise. Realizing that there wouldn't be enough time to save her Arkham inmates, Harley refuses Joker's invite to board the plane with him. As a response, he flies off without her, and attempts to dive into bomb with not only Batman and Robin nearby, but Harley as well.
The Relationship Between Harley Quinn and Joker: A Mad Love
Origin Harley as a doctor at Arkham Dr. Harleen Quinzel was a psychiatric intern at Arkham Asylum. A model student, in addition to receiving high grades in college, she was also a dedicated gymnast, winning a scholarship to Gotham City University. While researching the lunatics at Arkham, she became fascinated with one particular inmate. Ambitiously volunteering to analyze him, she pleaded with the doctors at Arkham for three months before she could treat him.
The Animated Series episode " Joker's Favor ",  in what was originally supposed to be the animated equivalent of a walk-on role; a number of police officers were to be taken hostage by someone jumping out of a cake, and it was decided that to have the Joker do so himself would be too bizarre, although he ended up doing it anyway. Thus they created a female sidekick for the Joker; she would become his love interest. Arleen Sorkin , a former star of the soap opera Days of Our Lives , appeared in a dream sequence on that series in which she wore a jester costume; They used this scene as an inspiration for Quinn. Mad Love recounts the character's origin story.
Who is Harley Quinn? Harleen Quinzel before falling in love with Joker Source: When Joker was captured, she took great interest in him; she spent most of her time trying to understand Joker. Harley Quinn and Joker: Internet From time to time, we can see that Harley Quinn has a great passion with Joker.