"Runaway Locomon" is the first of two Digimon TV movies set in the Tamers era. The gang plans a surprise party for Rika, but our favorite Digimon Queen is a little more upset than usual. We find out she's the way she is because her dad left her years ago. Now, the Tamers must do battle with a loose train Digimon while trying to cheer Rika up.
This episode/movie has several highlights, but the biggest is Rika's "Promise" song. Melissa Fahn (the voice of Rika) is truly magnificent in this scene, as not only do we get some insight on why Rika acts the way she does, but we also get one of the greatest anime songs of all time.
So, in conclusion, "Runaway Locomon" is recommended especially for Rika fans like myself. Just make sure to get the tissues ready when you get to the "Promise" sequence.