In The Hobbit : The Desolation of Smaug Thranduil offered to help Thorin to get Erebor 's starlight crystals in return but Thorin refused .
Thranduil offers helps towards Thorin in exchange for starlight crystals in Erebor But Thorin confronts Thranduil about his neglect of the Dwarves of Erebor following Smaug 's attack 60 years earlier , and is consequently imprisoned with the other Dwarves .
The Hobbit-COLON- The Desolation of Smaug