It is that good! Many contend that it is easy for an actor to perform in the role of a mentally challenged individual, as the actor must only perform his craft in a one-dimensional range of human emotions. My contention is that an actor's true abilities shine when he/she is asked to perform outside of the range of common, everyday human interaction.
Although Sam has his peculiarities and autistic routines that should not be disrupted - Wednesday is video night, Thursday is dinner at IHOP, Friday is karaoke night - he manages to spend much time with his daughter, Lucy (Dakota Fanning). He named her after The Beatles' Lucy in the Sky with Diamonds and he is very successful at providing for her emotional needs. As she turns eight-years-old and begins to surpass the intellectual capacity of her father, government authorities want to take her away.
Remember the name Dakota Fanning. She delivers a mesmerizing performance that is guaranteed to garner her many leading roles to come. She has that magical spark in her eye and her working chemistry with Penn allows their performances to rise above the screen. Their cohesiveness reminds me of that between Sam Rockwell and Mischa Barton in Lawn