Nia is nervous about working with Tess, the fastest -- and bossiest -- crane on Sodor! When Nia's plan for a safe and speedy delivery goes awry and causes Tess' wheels to clog with sand, they recruit handy Sandy to solve their problem. Luckily, Sandy has a new invention to get Tess up and going again: a tanker full of her Super-Slick Easy-Greasy Crane Grease! However, chaos continues to ensue when Nia gets stuck in the mud and the runaway grease spills all over Sodor! In the midst of the madness, Nia learns how to fix her original plan and save Sodor from slipping and sliding!