A wannabe activist who aspires to join a larger action group gets a job at a mysterious energy company he believes is involved in illegal activities.
What does he want to be active about? I’m guessing it has something to do with environmental issues. But a logline should not leave a reader guessing what the role of the main character is. So be specific: “An environmental activist….”
What becomes his objective goal as a result of joining the energy company? What specifically does he want to uncover, to expose? “Illegal activities” is too general, can cover a wide range of malfeasance. In “Erin Brockovich” the protagonist must prove that a plague of illnesses in a community is the result of the energy utility dumping toxic waste into the groundwater.
Sounds like a promising idea!
Just make sure to be more specific in your wording. He needs to have a clear outer goal (want) that is properly described in your logline.
And yes, “environmental activist” sounds better than just “activist”, because it gives the reader a clear vision of the main character and his background.