I don’t have the book that goes with this deck with me, so I’m going on past interpretations of the card, coupled with my impressions based on the illustration.
Our little fey mermaid or possibly a selkie, is swimming with what appear to be seals, but she’s sort of floating in the water, looking down, maybe sinking down. Fours are stability, and the Cups are associated with water/emotions. Maybe she’s down in the water to get away from life on the land, had enough of that life. She needs time to be on her own, and sort things out. The seals look like they’re swimming around having a good old time, but she’s not paying any attention to them.
The Four of Cups is usually about dissatisfaction with something, a situation or person. This card can signify a time to reevaluate a situation/job/relationship. Maybe it’s not all it was cracked up to be, or no longer meets your needs. The danger of course is in becoming so self-involved that we miss other opportunities while we’re busy contemplating our navels. It’s ok to reassess things, but don’t let it get you down. Things change. Nothing stays the same forever.