The Green Man's Holiday. The Green Man, #8

When your mother's a dryad and you're an only child, you don't have much experience of big family events. But Daniel Mackmain's girlfriend, Finele, has a whole load of relatives. They're all coming to her sister Iris's wedding. Frankly, Dan's dreading it. At least plenty of other guests will have connections to the supernatural. The bride and groom can turn into swans, for a start. Since Dan's still a loner at heart, he and Fin have planned a few days away together afterwards.
Just the two of them in a quiet country cottage should be nice and relaxing. Dan should have remembered what folk wisdom says about making plans.