Picking up right where The Farthest Shore left off, Tehanu shows us the life Tenar chose to lead after The Tombs of Atuan, and her encounter with Ged when he returns to Gont following The Farthest Shore. Unfortunately, the book doesn't really have a story to tell (though it's full of portents and stories of goings-on elsewhere in Earthsea). It is, effectively, the story of two souls on a remote island who are no longer part of the larger tapestry.
Which would be fine, except why bother writing a novel set in Earthsea about such people? The charm of the trilogy was that it was Ged's odyssey through a pivotal time in the history of a remarkable world and how he contributed to it. Tehanu shows us nothing new about Le Guin's magical world, and has little interesting to say. It's at its worst when the musings about "mens' work" vs. "womens' work" and "men's power" vs. "womens' power" comes out; Le Guin has nothing provocative or excitings to say here, and no conclusions - satisfying or otherwise - are reached. It's as if Le Guin felt self-conscious that the trilogy was so male-centric and wanted to rectify that. But it comes at the expense of the wonder that made the trilogy great fantasy. It's a small book about small people.
Worst of all, the book falls completely apart at its climax, as the narrative becomes muddy and rushed, with a finale which has little meaning in the context of the rest of the book.
Tehanu shows that you can't go home again; the trilogy was 20 years in her past when she wrote this, and Tehanu neither extends nor expands on it. If you loved the trilogy and want to read more like it, look elsewhere.