The series starts with Bruce Banner trying to cure himself of his "Hulk disease". I would have loved if the series showed in the first couple of episodes how he became the Hulk in the first place.
Almost each episode brings a different Marvel character for a fight with the Incredible Hulk, including Iron Man, the Thing and Ghost Rider.
Later on the series, the Gray Hulk and the She-Hulk join the cast. Their major enemies throught the entire series are the Leader and Doctor Doom.
The first season is great. The second season isn't so great, but it's still worth watching.