Complex sentence: Sometimes only two or three of James's friends will accompany him on an adventure, leaving the others behind at Warfield to create a B-plot which normally revolves around Trevor's misguided attempts to get James into trouble.
Split into simpler sentences: Sometimes only two or three of Jr. 's friends will accompany him on an adventure, leaving the others behind at Warfield to create a B-plot. These plots normally revolve around Trevor's misguided attempts to get James into trouble.