Drayduh Cove is an episode of Venturian Battle, part of the "Venturia" story arc.
In 1400 AD, Queen Drayduh lost her young son at an estuary. As such, she went mad with grief. She convinced the Red Magus to turn her into a sea serpent so she could find her son and bring him back from the dead. The sorcerer warned her, if she did not find him, she would remain a sea monster for all eternity. She never returned.
Cut to 300 or so years later, the current time period of Venturian Battle and Venturia, where the Jacob Knights are on a raft, sailing to Drayduh Cove, an inlet named after the queen. Upon entrance, they find Red Magus and Lemony Slave, who tell him the gremlin soldiers have seized control of Drayduh Bay, cutting off supplies to the region. He tells them they shall ally and take a stand against the gremlins, but they must kill the Gremlin Sergeant General and take his Crystal of Deflection.
Robert Jacob finds a boat and smashes it, then builds an object from it. Robert also finds a skeleton, then takes a shovel from a skeleton lying on a stone. Robert hands the shovel to Terrence Jacob, who digs up an object, and finds a lock which he breaks. Robert looks in it and finds a chest. Terrence puts aside the crate, though, and instead chooses to shove the previously assembled object into the puddle.
Tyler Jacob crosses, then puts his blade in a mechanism, activating a bridge ladder. Robert moves the chest along through the isles, then reduces it back to wood and builds an object. Robert jumps over it and turns a winch, lifting a ladder for his companions. Terrence drinks a Destructive Elixir, then opens an ingress to a lighthouse. After getting in, Terrence gets a torch, but accidentally drops it and lights a fuse. Robert realizes this is a genius plan, and orders Tyler to repair a mechanism. He turns the mechanism, placing it in the pipe in the ground.
Athens decides to help, spinning the helm, filling the pipe with green oil. Robert runs downstairs and sets the mechanism on fire with a torch. Terrence does the same with the two other pipes. Tyler then uses the eyeglass, and observes a swimming Gremlin Warrior, and warns the others. Half of the Knights are not in the lighthouse, and fight the gremlins, some of which live long enough to destroy an onyx. Meanwhile, Robert exits the tower and moves a wheel, then picks up some Acetone Peroxide, placing it near the tower.
Elsewhere, Prisco finds a ferry, and has Lemony sail him to the platform. Prisco picks up the explosive material and gets to shore. Cyan gets ahold of it, moving it while walking over the wood, then places it on a lift. Terrence, on the tower, pulls out the TNT and puts the chest on the floor of the lighthouse, while Tyler puts the bombs on the wall. At the end, Athansios sets everything on fire with a torch, exploding the lighthouse.
Noticing the ruin from afar, the Gremlin Colonel orders his Gremlin Army to attack the Knights. As the Jacobs make it past the waterfall, Boyce notices the "pig gnolls", and tells them to ready their arms. Many are defeated, with Magus burning several, but he gets hit himself, splattering white booger blood all over the floor. This triggers Lemony, who furiously chops millions of gremlins down, until Scottie tells Lemon they have a Potion. The health potion revives the Archimagus, and the Gremlin General finds them. The brothers attack with swords and guns, while the Autothaumatugist Magus blasts from afar with his wand, and Lemony the warlord attacking with his axe when the Gremlin least expects it, eventually triumphing.
Robert takes the golden Crystal of Deflection the Gremlin was wearing on his head, while Cyan notices a map. Boyce says they must use the map to go to Waldurc Woods, with Lemony joining their mission, while Magus sets off to the Hallows of Nathooz. Robert looks off to the wreckage, and tells them that the quest is going to lead them to great fortune and glory.