Nigeru Natsu

In the Nacchan no Romantic Love series:
V.1 - Kimi wa Ima mo Kimi o (僕は今も君を)
V.2 - Naisho de Kiss o Shiyou (内緒でキスをしよう)
V.3 - Nigeru Natsu (逃げる夏) (Summer of Escape)
A collection of short stories.
The title story focuses around Chihaya, who has a crush on Morisaki. However, the flower arranging school she inherited from her father isn't doing well, and her step-mother wants her to marry into another school to revitalize it. Chihaya disobeys her step-mother and runs away, only to be later rescued by Morisaki. Unwilling to go back home, Chihaya starts to spend the summer at Morisaki's place, painfully aware of the situation... though Morisaki doesn't even seem to notice.
- Storm in Heaven