The magic box with built-in mirrors makes part of its interior disappear through the redistribution of appearances. This box on the stage is a metaphor for contemporary life, being in the spotlight of the public, yet striving to conceal its secrets. By veiling certain spaces with the appearance of the surrounding environment, the mirrored magic box resolves the conflict between the pursuit of transparency and the emphasis on privacy within modern interiors. This paper explores a series of contemporary interior designs featuring mirrors, elucidating the potential of mirrors in addressing the tensions between the public and private, the interior and exterior, and in hiding while implying the secrets behind modern life. It further argues that these spatial concepts of the mirror can be traced back to the modern masters Adolf Loos and Le Corbusier, who pioneered the creative use of mirrors in dealing with threshold spaces.