(CH1) And Then There Were 10:

Raymond Tennyson is Ben Tennysons little brother (by five months). He joins Ben on a summer camping trip with their grandpa and cousin. After his brother finds a device known as the Omnitrix, Ray slowly learns a dark truth about his life. And during this new adventure, his relationship with Ben takes a new turn.

Follows the events of the 2005 TV series, for the most part, from Ray's point of view. But I change and add a few things to have Ray more involved in the story.