Some days before Christmas, Dr. Watson finishes work with his patients and returns to Baker Street to find his friend Sherlock Holmes in a depressive mood. Watson tries to reanimate Holmes by showing him some unsolved problems of some of Holmes' clients and finally comes up with an invitation to Lord Brainstorming. The visit soon leads Holmes to a mysterious case: finding Queen Victoria's genealogical records.
Sherlock Holmes DS and the Mystery of Osborne House is a hidden object game where players entirely rely on the stylus to play. Players try to find the right items to proceed. Sometimes players need to combine items or try them in different places. There is a question mark on top of the touch screen, which helps players find hidden items. Some items lead to puzzles; while playing, the difficulty of the puzzles increase. Players are given a choice to get a little or total help for puzzles, which will decrease points from their score. When having solved a puzzle, players can play it again in the "puzzle" section and can earn points to unlock puzzles.
The game's graphics are 2D. You can save your process manually anytime in the "info" section. The maximum number of save slots is 3.