Microsoft has trademarked the title Secrets and Treasure. The trademark page only mentions “game software,” so we at least know it’s a game.
Gamespot adds that Microsoft registered the URL “secretsandtreasure.com” last February, though the URL currently only directs to a Bing search. This could be the Japanese title Microsoft was teasing this morning. At any rate, we will find out at this year’s E3 or before. Thanks, Gamespot.