This paper develops an original interpretation of Kant's argument for transcendental idealism in the Critique of Pure Reason. The distinctive feature of my interpretation is that it rejects the standard view that Kant's main, direct argument for transcendental idealism is wholly contained in the Transcendental Aesthetic. Instead I argue that the Aesthetic issues promissory notes that Kant cashes in only later in the Transcendental Analytic, so that his main argument for transcendental idealism is only outlined in the Aesthetic and is not fully developed until the end of the Analytic. My goal here is not to show that this interpretation is superior to others, but only to make a case that it is plausible and fits the text. I also suggest that my interpretation attributes to Kant a plausible argument for transcendental idealism, and that it helps to shed light on the nature of transcendental idealism as well.