[s7e10] Master Plan Here
Depending on how you are using the title in a sentence, the "proper article" changes based on standard English grammar: 1. Using it as a Title
If you are talking about the actual scheme or plot inside the episode's narrative: [S7E10] Master Plan
Are you writing a of this episode, or just trying to figure out how to label it in a collection? Depending on how you are using the title
Use this if you’ve already mentioned the plan or if it’s the primary focus. ("The master plan was finally revealed.") unique entity within the series.
When referring to the episode by its name, you usually use because it is a specific, unique entity within the series.