Complex sentence: At the end of the season, Walter indirectly helps cause the midair collision of two airplanes; the pink teddy bear is then revealed to have fallen out of one of the planes and into the White family's pool.
Split into simpler sentences: At the end of the season, Walter inadvertently helps cause the midair collision of two airplanes. The pink teddy bear is then revealed to have fallen out of one of the planes and into the White family's pool.