Presented without stats, because lazy.
5. Treasure Cave
Doors: North Door: secret; south door, partially blocked by rubble, but accessible.
Smell: Fresh air, water.
Light: Adequate and aesthetically pleasing, natural illumination enters the chamber from the surface through small breaks in the ceiling, during daylight hours. Evenings are lightless.
Inhabitants/Encounter: 2 Sea Monkeys live in the pond, along with any number of fish. Various rodents and other small woodland animals have nests within the cave, and/or use the fish as a resource. Dozens, if not hundreds of common bats sleep on the ceiling during the day, exiting through the fore mentioned breaks in the cavern ceiling. One giant, intelligent, talking bat lives among them. This fellow styles himself King Giles. King Giles seems nice enough, but in actuality, he is an asshole. Given the opportunity, he will descend from the ceiling and speak with the players. He will offer to sell them information for morsel of food. And tell them about the treasure chest on the lake bottom. As he approaches, Giles will shout at the players and assure them he means no harm. In fact, however, he is in collusion with the sea monkeys, who wait, buried in the mud of the lake bottom, on either side of the chest.
If the players attempt to remove the trunk from the bottom of the lake, they will find that a trick of the light has distorted the perceived depth of the water, which is much deeper than it initially appears. The trunk is firmly lodged in the lake bed, and it will come free 1d3 rounds after one or two characters beat a 5d6 STR check. The arrival of the PC's on the lake bottom will kick up a cloud of silt, unless they specify caution to avoid doing so. 2d6 Dex save.
However, the sea monkeys will attack once the players are engaged in the act of raising the trunk. They will gain surprise by swimming through the cloud of silt. If there are PC's on the shore or on the water (in the boat from room 4, perhaps, they will be able to see that something is going on but unable to tell exactly what. At any rate King Giles, and 1d12 of his bat minions will attack any characters on the surface.
The trunk is locked, but there is no trap. When the trunk is opened the screaming wight trapped inside it will leap out and attack the nearest character. Otheriwise, the trunkis empty. Lol.