After discovering the possible location of another Horcrux, Harry and Dumbledore travel to a seaside cave where Harry is forced to make Dumbledore drink a painful potion that hides the Horcrux, a locket.
After discovering the possible location of another Horcrux, Dumbledore requests Harry's help to retrieve it. They travel to a far-away cave where Harry is forced to make Dumbledore drink a painful mind-altering potion that hides the Horcrux, a locket.