Memory is pictured here as a sea, or a marsh, where strange creatures move beneath the surface. The speaker finds violence and passion in it: crusaders with flaming crosses, buried loves and knives, old gowns stored like castoffs in an attic. These dark things feel as ordinary and as much a part of her as a half-raked lawn.
The poem keeps shifting between "I," "you," and "we." The speaker senses that another person carries a similar inner world, and that the two of them share a passageway, but they stay private. She doesn't want to "enter anyone or be entered," even though nothing is truly lost. Smells of incense, garbage, and perfume mix together, so memory feels both beautiful and rank.
The mood is thoughtful, wary, and a little lonely. The last lines suggest that even close people wander separate forests and "never quite meet."