Rick doesn't care about saving the world; he cares about his toaster working again, and that casual disregard for stakes is the entire joke. Morty gets dragged into a mecha battle in Akihabara over a screw because that's how Rick operates: the absurdity isn't the destination, it's the refusal to take any of it seriously. The special knows exactly what it is and doesn't apologize for the randomness.

A broken toaster sends Rick and Morty hunting for the right screw in Akihabara, where an old rival turns a simple errand into a full blown confrontation.