Doctor Lautrec and the Forgotten Knights , a puzzle-based adventure with strategy and RPG-elements mixed in, follows the adventures of Professor Lautrec , a professor of Archeology at the Museum of Natural History in Paris, at the end of the 19th century. He has recently heard rumours that there is an underground system of dungeons beneath the city, and that there is treasure there that could be linked to Louis XIV. Weirderly enough, it is said that the treasures are somehow alive and protected by the spirit creatures inhabiting them.
To find the treasure, players have to follow a quest through to the end. Each one starts with the treasure map obtained at Le Repaire, which consists of a cryptic riddle. Doctor Lautrec and Sophie discuss the riddle with no active player input and eventually this results in a number of possible locations. These can be visited in turn, either to find NPC's giving them more clues, a dead end (in which case more discussion follows) or the entrance to the dungeon.
Once inside, the player explores several floors of the dungeon, each containing several rooms filled with traps, guards and/or crates. Each room requires a different approach, for instance pushing crates into gaps in traversable walls, avoiding the guards or timing your way around flaming arrows being shot at regular intervals. Some rooms have chests containing jewels that are optional but can help later on. Each dungeon has one main treasure room and several additional treasure rooms, each with a puzzle lock.
Once open, the treasure room reveals an egg containing the Treasure Animatus. Sophie reveals which kind it is (there are five types that have strengths and weaknesses against each other in a rock-paper-scissors kind of way) and the player has to place treasure already in their possession from earlier quests and the jewels from the chest on pedestals around it to 'tame' the spirit.
The goal is to do enough damage to get a meter into the red zone. Doing too much damage leads to the spirit being 'extinguished', which makes the treasure worthless. This can also happen to treasure you have placed on the pedestals. It is possible to revive 'dead' treasure with special stones you can buy at the Tavern, but these come in five types as well and you can only bring three into the dungeon with you.
As soon as the Treasure Animatus from the main treasure room is tamed or killed, Lautrec and Sophie are transported back to Le Repaire, where after a cutscene a new quest can be started.