Its pretty awesome, its a slow start but stick with it til the end of Season 1 and you're hooked.
Ill try to explain the overall story without spoiling events that happen.
Theres a multitude of Houses and Families but the 4 Main Noble Families are The Lanisters, The Targaryens, The Starks, and The Baratheons. All fighting for the Iron Throne.
Before the current King Robert Baratheon ruled The Iron throne was in the Hands of The Mad King Aeyrs Targaryen who while was once a kind and noble King he slowly went insane and began a murderous rule, So Lord Eddard Stark and his long time friend Robert Baratheon led an Uprising against the King to have the Realms be a peace. In response to this The Mad King set the Entire Kingdom Ablaze in the hopes that he would walk into the fire and fulfill his Families destiny and become a Dragon and destroy all his enemies and those that stand in his way.
But the Kings right Hand and most trusted Knight Jamie Lanister stabbed him in the Back before he could walk into the fire after hearing his nonsense and wanting to save the Kingdom.
Yada yada Robert and Eddard won and now Roberts the King and Married Jaime Lannisters Sister and made her Queen.
Now they rule Kings Landing.
Aerys Targaryen sent his Son and Daughter Viserys and Danerys far away with 3 dragon eggs to be kept safe during the rebellion in the hopes that they would one day come back and take the throne that is rightfully theirs.
A couple years pass and you now have Episode 1.