Machiko is a caregiver at a nursing home, Shigeki is one of the residents. Machiko is grieving the (apparently recent, though it's unclear) death of her young son, while Shigeki still mourns the loss of his wife, 33 years earlier. Their relationship to each other and to their grief during an excursion when they get lost in the woods. Their bond is complicated by Shigeki's dementia, whose often childlike behavior surely resonates with Machiko. It's an interesting, contemplative and spiritual exploration of grief with some lovely moments. Without spoiling anything, a charming early scene of Shigeki at the piano takes on a heartbreaking twist. Later, as Machiko desperately tries to control his reckless quest through the forest, we get hints of how she lost her child and the unresolved feelings she has.
Although there are gorgeous scenes (the two playing amidst rows of geometrically carved hedges, for example) the hand-held cinematography isn't doing the film any favors. It may have been more appropriate in the latter half, as their journey takes them deeper into the wild. But the shaky camera-work throughout the entire movie adds nothing. Maybe it just comes naturally to Naomi Kawase, whose work is primarily in documentaries (although she's no stranger to drama).
I don't know if this is an accurate representation of a Japanese senior facility, or an idealized one. I know that respect for elders is more ingrained in their culture. The home certainly appears to be a great deal more comfortable, dignified and serene than what we have. Perhaps it's a very expensive one, though we get no hints that Shigeki is particularly wealthy.
I thought it could have explored its themes a bit deeper, and there are the aforementioned camera issues, but overall I liked the film a great deal. It ends on a strikingly beautiful note. I'd like to see more by Kawase.