Complex sentence: However, Tauriel leaves to help the injured Kili and a concerned Legolas gives chase, while at the mountain, Bilbo deciphers the Last Light of Durin's Day clue and uses the moonlight to locate the hidden keyhole that opens the secret door into the mountain.
Split into simpler sentences: However, Tauriel leaves to help the injured Kili and a concerned Legolas gives chase. At the mountain, Bilbo deciphers the Last Light of Durin's Day clue and uses the moonlight to locate the hidden keyhole that opens the secret door into the mountain.