They found out that recently some ships had been sunk by sahuagin, also they seemed to only go after very specific targets. The most recent case was the Aurore, sunk 20 miles east of Port Torvin. A surviving sailor, currently in Saltmarsh, told stories of a giant two-headed shark controlled by sahuagin who had sunk the ship. The ship was transporting a crate with a magic item from Port Torvin to an island near Saltmarsh. The group was able to find the sailor, Edwin, currently drowning his sorrows in a local tavern. He told them his fantastic story about the attack of the two-headed shark, who had ripped a huge hole into the side of the ship to sink it. There had been sahuagin riding other sharks around, but they seemed content to sink the ship, and didn't go after the survivors in the lifeboats.

With the help of their religious knowledge and the local priest, Wellgar, in the temple, the group managed to get some more clues: The shark was probably the Maw of Sekolah, an avatar of one of the sahuagin gods, kept in their underwater city of Akriloth. While Shayla, one of the group's clerics, worships a more common aspect of Helm as a god of protection, the sahuagin, who hate magic, worship a lawful evil aspect of Helm as a protector from magic. This is because Helm had to destroy Mystra, the goddess of magic, during the godswar. Due to that event, Helm shed a tear, which crystallized into a large elongated gem with strong anti-magic powers, the Guardian's Tear. The group believes that the sahuagin are somehow identifying the ships that carry magic items, and sink them.

After letting their crew celebrate in the evening, the group's pirate ship sets off the next morning towards the general location of the sunk ship. As sunk ships don't leave traces on the surface, that turns out to involve two days of searching while diving. Finally they come upon the Aurore, with a big hole in the side. Entering the ship through that hole, they come across a huge floating fish eye. The group attacks the eye, but it turns out to be insubstantial, so the eye just looks at them, blinks, and disappears. Searching the ship the group comes across several drowned wights. After defeating those, they find the crate with the magic item, plus a large stash of 500 gold and 3000 silver coins, as well as the cargo manifest, protected from water by being bound in a leather case.

When trying to leave the ship with their loot, the group comes across a sahuagin patrol, alerted by the eye earlier. Shayla contacts their leader telepathically and tries to negotiate. The sahuagin are willing to the group go, but they would have to leave their magic treasure behind. Not willing to do so, combat ensues. Bubu, the tabaxi wizard and captain of the group, particularly enrages the sahuagin by his use of magic. The heroes manage to defeat the sahuagin, and with the help of their crew and ropes transport the treasures onto their ship. As usual, the crew demands half of the cash, which they are being paid, despite some reluctance on the part of Bubu.

The crate contains a staff of healing. They also looted a sahuagin trident from the patrol that Gris can use. The cargo manifest reveals that the Aurore was in fact run by the pirates of the Hold of the Sea Princes, as part of their smuggling operations. Apparently several transports of magical items had gone to the Isle of the Abbey, a small island near Saltmarsh.

Back in Saltmarsh the group asked the lighthouse keeper for information about the Isle of the Abbey. It turns out that the abbey in question is one of some evil cult, who is protecting the island with skeletons buried in the dunes at the south tip of the island. There are also rumors that the northern part of the island is not only hard to access due to rocks in the water, and cliffs that need to be climbed, but also a bone dragon guarding that part. Major Ursa can also tell the group of recent events, observed by people from Saltmarsh fishing near the Isle of the Abbey: Several pirate ships came and raided the island. The pirates landed in the dunes to the south. A column of smoke was seen from the center of the island later. Then the raiders returned to their ships and left the island.

The next day the group heads out with their ship to the Isle of the Abbey. They land at the same spot as the pirates, trying to find the way the pirates used to cross the dunes safely. That mostly succeeds (with a series of survival checks), but at one point they take a wrong turn and are attacked by 10 buried skeletons. However the group has 2 clerics, both of which use turn undead, and now at level 5 that actually destroys skeletons. This makes the encounter rather easy, and the group manages to cross the dunes without further problems. In the center of the island they find the burned-down abbey. A search reveals a staircase leading to the cellar. They sneak downwards and come into a large cellar room with several doors. A burly draconian warrior is sitting with an acolyte at a table, playing at dice. At this point we end the session, to be continued next time.

Note that hunting for treasures was an idea of the players; the events on the sunken ship I invented myself, using a generic battlemap of a sunken ship; and the Isle of the Abbey is one of the adventures in the Ghosts of Saltmarsh published book.