Lanke was one of the midshipmen aboard the Obra Dinn alongside Peter Milroy and Charles Hershtik. Being an officer-in-training, he assisted higher-ranking officers and tradesmen in order to learn the ship's operations. He was frequently seen with the other midshipmen.
Lanke and the other midshipmen witnessed the retrieval of the mermaids as they were taken down to the lazarette. They also fought off some crab riders, one of which Hershtik killed. However, he got impaled and burned to death.
When the ship was attacked by the Kraken, Lanke and Milroy got cartridge bags from the gun deck, intending to throw them at the beast. When the Kraken grabbed Milroy and started thrashing him about, Lanke tried to pull him to safety with a rope but the cartridge bag exploded, killing Milroy and severing one of the tentacles.
Shortly after the Kraken attack, Gunner's Mate Olus Wiater and Fourth Mate John Davies considered mutiny, planning to take over the ship and sell the "wretched fish" and shells. Lanke overheard their mutiny plan and immediately panicked, yelling "Mutiny! Mutiny!" at the top of his lungs. Wiater stabbed him in the back for his trouble, and Davies intervened while Lanke crawled to the midshipmen's cabin.
After the two would-be mutineers got killed in the resulting dust-up, First Mate William Hoscut ran to Lanke's aid. Before dying, Lanke asked Hoscut to tell Milroy's mother that Lanke tried to save Milroy during the Kraken attack.
The East India Company insurance assessment of the Obra Dinn incident awards Lanke's estate £30 in outstanding wages.
Lanke must be identified through the process of elimination by identifying the other two midshipmen first. This is possible after seeing A Bitter Cold, part 3 and Escape, part 6. Lanke's cause of death can be figured out in Escape, part 4 where he crawls on the floor with a knife jutting from his back. His attacker is revealed in Escape, part 3.