The Mutual theme for 2015 is D&C 4:2:

“O ye that embark in the service of God, see that ye serve him with all your heart, might, mind and strength, that ye may stand blameless before God at the last day.”

The theme may be used in Mutual opening exercises, as a topic for sacrament meeting talks by youth, and to provide focus for youth activities, including camps, youth conferences, and devotionals. It may also be used to guide youth in Christlike service in their homes, the temple, the Church, and the community.

Resources for introducing the theme, including videos and music, will be available online by the end of 2014. Additional materials supporting the theme will be made available in Church magazines and on LDS.org throughout 2015. Below are a few images relating to the theme that I found online: