To be clear, without spoiling anything, the place in which the shorts are located is initially unavailable to you. As others have said, you can see them on the screen if you're in the right place and paying attention... but there is something that blocks you.
Now... someone has lost their shorts. While this may seem like an innocent sort of thing, let's think about this. How does someone lose their shorts? If they weren't wearing pants, even short pants... it would look odd as they're wandering around town, yes? So maybe the person that lost their shorts lost them in the house! Well, Lewis' house is pretty small, and after a thorough search it is easy to realize they aren't there. Where else could someone lose "shorts"? And in what scenario would it not be weird when they're strolling home without "shorts" on? The secret is to start by taking those questions in the reverse order and to start by thinking like the Brits when we hear the word "shorts", because when they hear it, they're thinking "boxer shorts", not "short pants". Now, those you can easily leave just about anywhere and still have your trousers on to conceal your shame... and if we then continue this line of thinking, we see what we really need to be thinking about is, "Where might some fellow lose his boxers that aren't his own house/bedroom?"
