This is the first season of the series and it will tell you the story of the main leads before they got to where they are now. Which will help you make sense of it all if you are looking to watch Switch Girl 2 which is picking up where the first season left off.
sequel to the first drama and they both have the same female and male lead roles
They both are very similar though SG focuses more on romance and SBK focuses more on friendship bonds and fighting.
Hayami Honoka works in the sales department for a major consumer electronics company. She is excellent at her job and is respected by her colleagues. She seems like a clean freak at work and her colleagues think she is a perfect person to marry. But, in her private life, her home is a complete mess. Things there are unorganized and dirty. On the flip side, when she arrives at work, she looks perfect.
Meanwhile, Yamamoto Chihiro is Hayami Honoka's co-worker in the same department. He joined the company 3 years after Hayami Honoka. When he was a child, Yamamoto Chihiro and his two brothers did the housework at his home, while his mother was busy with her job. Because of this, Yamamoto Chihiro is excellent at doing household chores. Due to a case, he happens to learn that Hayami Honoka's home is a mess. He begins to stay with Hayami Honoka on the condition of doing the house work.