[3] The main heroine of the series is a rabbit named Mell, who is meant to be a character that expresses the feelings everyone has, simply stating "Thank you", "I am sorry" or "I like you!

The series debuted on December 27, 2010, and is officially targeted toward girls ages 15–20, mainly high school and college students, who were too shy to express their feelings toward others.

Sanrio stated that her official release describes her as being "withdrawn" and implores her fans to send her as many messages and Tweets as possible to encourage her to show her face, leading to criticisms of her being a hikikomori.

[5] An official Ameba blog, Facebook, Twitter and Vine account were made for the fans to interact with the characters of the series.

Maimai is based on the Japanese pop singer Mai Kuraki, who collaborated with Sanrio on releasing the series's image song "Stay the Same".

[11][12] On October 2, Sanrio will introduce another collaboration to the series, with two several teaser blogs showing a new character's arrival in Merci Hills.

[13][14] In October 6, the character is revealed to be Buzzy, the official mascot of Karel Capek, a tea shop in Japan.

[15] Sanrio announced the collaboration with Karel Capek to make merchandise and tea-related goods based on the Wish me mell series, with illustrations from Utako Yamada.

[16] On October 12, 2012, Sanrio released several stamps of the Wish me mell characters for the instant messaging software LINE.

Mell is then introduced to another friend from Australia, a koala named Lou who recently moved into the Hills to study.

One day, the egg that Poco entrusted to Mell started to crack and later hatched into a young dragon girl named Nina.

However, during the fortunate event, Mell received a special letter from the college students in Japan, saying that she can deliver and connect the feelings of everyone there.

Mell accepted the mission and decided to cross the Rainbow Bridge, leaving Merci Hills as she ventures to Japan to connect everyone's feelings in the human world.

[7] The second chapter of the series focuses on Mell visiting the human world for the first time as well as introducing to two new characters in Merci Hills: Roseanne and Maimai.