Mihoshi is from the planet Seniwa and is a member of the prestigious Kuramitsu family whose power in the Galactic Union is second only to the Royal Family of planet Jurai.
Like the rest of her family, Mihoshi joined the Galaxy Police, eventually becoming a Detective First Class. Mihoshi was known as one of the finest officers in the Galaxy Police, but her career soon hit a major roadblock after an incident hinted at in the 4th and 5th episodes of the 1st OVA, and the 4th episode of the 3rd one. It has been alluded to that the incident involved an arranged marriage, which would factor in the Chobimaru incident later in the series.
Now, she suffers from frequent difficulties to focus on a single thought track and due to her clumsiness, she causes a lot of collateral damage during her assignments, which eventually causes Mihoshi to be demoted. The desk of the Section 7 commander is covered with misconduct reports and bills from all the damage she causes. As a result, she is assigned to a special remote area of the galaxy, the developing Solar System, which is Juraian territory, in the vain hope that she wouldn't cause any more trouble.