Master ball
you have to talk to buck's grandpa first, then get through stark mountain with buck. Once you get through, go back and to talk to the grandpa, then go back to stark mountain. Heatran should be there at level 50. Bring lots of dusk balls.
On the T.V. show, I think they're about the same tough and strong. But all my friends and I believed that Heatran is stronger than Giratina. Heatran's most powerful moves are almost all power over 95.But Giratina's moves are also very good, but not as powerful as Heatran's. Although Heatran's speed is lower than Giratina's, Giratina has an advantage. But still not stronger than Heatran. But in the Pokemon TV show, there like the same strong.giratina beats heataran because fire is dissafective to dragon and when giratina is in orgin foarm ground moves wont work on it