Episode 21 of "ReGenesis"
s02e08 Haze

Bob's attention turns to the escalating danger in the skies over Mexico City where a massive brown cloud has begun to combine with toxic emissions from a nearby volcano. The new mixture could rain sulfuric acid down on the city and Bob must try to convince the Mexican officials of the gravity of the situation before all of Mexico City is destroyed. Homeland Security is monitoring two scientists in Chicago who they believe are a threat to the U.S. president. After testing samples taken from their lab, David feels the investigation is unwarranted. Caroline, however, can't shake the feeling that something is wrong. Ultimately, there's not enough evidence to detain the brothers and they are set free – but at what cost? Owen shows up at David's office looking for a place to stay.