Ellis and 'Neck' are fourteen year-olds dealing with issues common to their age, but a shared passion for boating gets them close to a boat with potentially no owner in an uninhabited island and a fugitive named ‘Mud’ running from the law for defending a damsel in distress.
Neck follows Ellis' lead and both begin helping Mud, but that fragile alliance is put under test when people come to town looking for Mud and his girl.
Mud is a coming of age story with dramatic elements that distinguish this film from the rest in its genre. Ellis is a boy dealing with a tense home life and the no-nonsense life education his father is imprinting in him. He is a good friend and can't resist jumping to the rescue of a lady in trouble even if it means getting a black eye or his butt kicked. All those things bring Ellis and Mud closer, but is Ellis becoming a better person with Mud's help? Or, is Mud using both Ellis and Neck?
There's very good acting in Mud starting with the title character interpreted by Matthew McConaughey—we seldom get to see him in dramatic, demanding role and this is definitely a good sample of what he can offer. Also notable are Tye Sheridan as Ellis and Jacob Lofland as Neck, Reese Witherspoon as the sleazy Juniper and Sam Shepard as Tom, Ellis' neighbor and adopted father to Mud.