Juliet was deeply in love with Romeo and hoped to marry him, since he promised to do so during their childhood. However, Romeo did not have the courage to tell her about his feelings, so she thought he didn't love her. In the end, they admitted their feelings for each other.
Juliet has an Illumise that she accessorized with a yellow bowtie with a red core that has a blue trim. Illumise fell in love with Romeo's Volbeat, Beat. She first appeared practicing with Beat. However, Romeo's clumsiness got the better of him and caused them all to fall into the water. Illumise almost drowned and had to be saved by Brock's Mudkip.
Later, when seeing a light on the other side of Lake May, Illumise followed it but it was actually Meowth dressed up as a Volbeat. Team Rocket captured Illumise with a net. The next day the gang found Team Rocket. Jessie sent out Seviper to recapture the vulnerable Volbeat, but she used Sweet Scent to lure the Volbeat away. Pikachu sent them blasting off.
In the end, Illumise along with the rest of the gang performed perfectly for the festival.