Psmith (the “P” is silent) has been invited to Blandings Castle. But the conditions under which he received his invitation are suspect. Probably because he is a suspect.
Doddering old Lord Emsworth has, indeed, extended an invitation for Psmith to come stay. However, his Lordship was under the impression that the sharp and attentive Psmith was in fact, the irascible poet Ralston McTodd.
But the quick-witted and resourceful Psmith knows a good thing when he sees one, and immediately puts several plans in motion. True, one of which does include the purloining of Lady Constance’s jewels, but another concerns a certain lady whom Psmith saw standing in the rain earlier, and felt obliged to present with an umbrella. Never mind that the umbrella wasn’t his.