From Renta!:

Midori Sasaki runs a green plants store. However, in addition to his greenery services, he also offers sexual services to a select few of the elite to attain his goal. One day, a client of his in both senses asks him to date his little brother. Though Midori is broken hearted, he visits the client's home only to be met by the belligerent brother. Midori decides to leave, but the brother stops him, demanding his money's worth! This is a clumsy and awkward love story that starts with a financial transaction.