The Green Ranger has a bit of a checkered past. Originally a villain, he eventually came around to the side of good. In this new scenario for Power Rangers: Heroes of the Grid, Rita Repulsa comes to get what she's owed from him. You can download this new scenario now.
From the announcement:
Once Rita Repulsa granted Tommy Oliver the powers of the Dragonzord to defeat the Power Rangers, he turned against her and used those powers to save the world. The time has come for Rita Repulsa to collect on the Green Ranger’s debts. Download Scenario #14: The Green Candle now!