You are a lone fisher sailing between a few scattered islands and you cannot sleep. Weird things happen, sometimes at night, and sometimes when the moon changes phase, but all are related to a loss in your past.
Sleepless Sea provides a map for you to explore, each one giving a distance between the islands. The time is tracked in 'Glimmers'. To travel, you need to roll d66 on an encounter table for how many glimmers and resolve each one. Some will give you fish, some will damage your boat.
To fish you roll 2d6. Depending on the result you might gain fish and/or deplete the reserve. You can then take the fish back to the docks and sell it to gain money or other items to help you fish. Each time you fish you also add 1 Glimmer.
The game isn't endless and your progress is tracked by the phases of the moon. Every 7 Glimmers, the moon phase shifts, and something strange happens. You start on the Full Moon and the game ends when you reach the New Moon.
My fisherman didn't do to well and was only able to bring 3 fish to the docks to sell. You can read my playthrough HERE
There was also a section on the RTF file I was a little confused about. It's labeled 'Card' and has further instructions for rolling Encounters. It talks about encountering a Visitor or a Creature and comparing the dice value to a 'Card' but doesn't say what or where this card is. This section isn't on the pdf and I don't know if this was cut content or not, but for my playthrough I just ignored it completely.