The show's titular character feels a bit old and wizened for his age. Arnold is always calm, cool and collected and never really gets upset. In fact, first appearances might have you thinking his half-open eyelids belong to a lazy or perpetually-sleepy kid, but it isn't long before the show displays his unique personality and the fact that there is an all-around good and laid back mind in that football-shaped head of his.
While Arnold and his friends are only nine years-old, they seem to have a good understanding about how their world works. Of course, a lot of that understanding isn't quite on the nose, and many of their adventures are the revelations that come from learning those mistakes. This typically comes in the form of some urban legend that is passed from "kid generation to kid generation," but when actually tested, proves false.
A good example of this is "Pigeon Man" where the kids hear a tale about a man who lives on one of the rooftops in their neighborhood and is part bird, part man. The legend claims he was born from an egg and that no one should go up and see him, else they will be sorry. When one of Arnold's carrier pigeons gets hurt though, he decides to be brave and bring the little guy to the fabled character. What he gets instead is an interesting lesson about how different people are.
Arnold has an unusual home life. He lives with his grandfather and grandmother who run a boarding home. As a result, he has a bit of an extended family. Included in this mix of characters are a demolitions expert with a Napoleon complex, a married couple that are constantly fighting, a Vietnamese immigrant and a super secretive man known only as Mr. Smith, who communicates only through security cameras.
Outside of his home life, Arnold is surrounded by his classmates. Chief among these are Gerald, Arnold's best friend who seems to be the custodian of the many urban legends the kids hear about. As important as Arnold is to the show, you can't have Hey Arnold! without the class bully, Helga. This shrew of a character does whatever it takes to get her way and is mean to everyone, especially Arnold. What she doesn't want anyone to know though, is the fact that her extra aggression towards Arnold is just a mask to cover up the fact that she is secretly in love with the kid.
There are quite a few episodes where this is the focus of the show. In one, Arnold is trying to connect with a sixth grade girl at the local fair, but Helga is determined to not only keep that from happening, but maybe even end up in the tunnel of love with her crush. In the show's Christmas episode, not only does Arnold try and teach a valuable lesson to the viewers about the thought that should go into a gift, but Helga spends her time trying to decide exactly what the perfect present to Arnold is that might finally let her confess her feelings towards him.
None of these events hold a candle to the season's final episode where Valentine's Day approaches and Helga sees this as an opportunity to express herself to Arnold. At the same time, Arnold decides to finally ask that sixth grade girl out, but he does so in an anonymous way. With Arnold trying to convince the older Ruth that he was the one asking her out, and Helga dressed up and acting like Arnold's long-time French penpal, things are bound to get out of hand... especially when that same penpal decides to make a surprise visit to the States.
This season is chock-full of great episodes and pretty much every one is unforgettable. Even without any special features, this is a great show for kids of any age, even if you didn't see the show when it first aired in 1996. Hey Arnold!: Season 1 is a must-see at least.