The series starts by stating: "Rather than being a person born in chaotic times, better to be reborn as a dog in peaceful times. However, there are some people who are born as dogs in chaotic times. This is their story."
Apart from being a terrific description of the Joseon yangban class as a nothing-goes entity, this series is a fun drama full of swagger and hysterical over-the-top scenes (drag queens, crazy elephant, horse acrobatics, magic). The result is an unconventional historical drama, where the lead character Eric Mun wears a black mask, has long hair, and rides off on his horse brandishing a whip under the moonlight.
The series occurs during the reign (1623–1649) of King Injo , the 16th ruler of Joseon . Injo was the son of Prince Jeongwon, who himself was the 7th son of King Seonjo , the 14th ruler of Joseon with Royal Noble Consort In of the Suwon Gim clan. The 15th ruler, King Gwanghaegun , was the 3rd son of Seonjo with RNC Gong of the Gimhae Gim clan and therefore the Injo's uncle. In 1623, Gwanghaegun was ousted of power by a political plot from the Western faction, that puts Injo on the throne. The turmoil of the civil war was thereafter increased by the Mandchu invasions of 1627 and 1636.
Two events are the cornerstones of the series and are stepwise described during numerous flashbacks. Both of them were instigated by the conservative Western faction. One of them is the bloody extermination of the "Rising Sun Utopia" (Muryun Dang), occurring during the year of the Snake (gisa year, 1629, Injo '6), and the other is the assassination of Crown Prince Sohyeon by his father in 1645 (Injo '22). The main action is situated circa 1648. While elements of these former plots are re-emerging from the past despite a series of murders, a group of mysterious assassins is avenging the sadness of the poor people.