Summer Story by Jill Barklem is a charming children's book, the second in the Brambly Hedge series, focusing on a, hot, lazy summer where the mice community seeks shade by the river. It centers on the romance between Poppy Eyebright and Dusty Dogwood, leading to their marriage aboard a raft. 
Description
Hardcover | JUVENILE FICTION/Animals / Mice, Hamsters, Guinea Pigs, etc. It was such a hot summer. The sky was deep blue and the sun never faltered. All along Brambly Hedge, the mice did their best to keep cool. Poppy Eyebright sought refuge in the mossy shadows of the mill wheel; Dusty Dogwood took to walking by the banks of the cooling stream. Dusty and Poppy spent more and more time together, so no one was at all surprised when they announced their engagement. They decided on a very unusual setting for the wedding ceremony, but even they did not realise just how unusual it would prove to be!