Leadership Next's Alan Murray calls the board shakeup at Exxon one of the biggest business stories of the year. And today the man behind that shakeup - Chris James of Engine No. 1 - joins Alan and Ellen McGirt to explain what inspired his activist campaign, and why he believes it succeeded.

Fortune's Katherine Dunn - who has been reporting on the story - has valuable insight to offer too, laying out how the proxy fight unfolded and why the moment was ripe for disruption.

Also key of course is what happens next. Will the three new board members be able to drive change at Exxon, pushing it to invest in the technology needed to transition away from a carbon-centered energy future? And does Engine No. 1 have its sights set on another company?