Jouvert took part in the unit's ill-fated mission to Vygoire, assigned to investigate a Dominion lab complex that had stopped responding to hails. Terrestrial and orbital observation showed that while the complex had suffered damage, it appeared to be from natural causes, such as a landslide. Jouvert was assigned command of one of the unit's fire teams, while the rest of the unit engaged in a support formation. As per urban-recon protocols, the facility was investigated.
After the investigation, which produced no living terrans, the unit headed north for a bit. Jouvert scouted ahead, reporting that the trail that led north from the base led to a ravine. After returning to base, Jouvert watched as Sergeant Norwood Doakes sent out a transmission for any surviving scientists, and failed to get a response. Milner suggested that they were all dead, and Jouvert asked what could have killed them—the zerg had been cleared out from the world years ago, and they hadn't seen any creatures large enough to cause bodily harm. To further compound matters, the Scion (the unit's battlecruiser and transport) had to be called out-system for emergency escort duty, but advised the unit that it would contact them when it was back in-system. The unit would continue recon duty in the meantime. With the transmission ended, Jouvert joked that they'd better start constructing houses.
The marines headed back to the ravine that Jouvert had scouted earlier. Chen investigated a nearby clearing that showed signs of a large creature having previously moved through it. As if on cue, a roar sounded through the jungle, and one of the marines started freaking out, screaming about coordinates, gods, and a "Great One. He ran into the jungle, only for an ultralisk to come running right at the unit.
Jouvert and the platoon as a whole managed to survive, after which they came into contact with the scientists they had been sent to retrieve. Apart from one of their number, they were acting like cultists, calling the ultralisk the "Great One" and offering themselves up to be sacrificed. So when the ultralisk came again, and the scientists began their process of "communion," the marines were able to escape again. Doakes ordered them back to the complex, where the only remaining sane scientist (Dr Vera Langridge) explained that the scientists and ultralisk had been infected by a type of psychoactive spore, one that had likely infected the marines as well. Having had enough, Jouvert exclaimed that they should leave the scientists to their fate, call in the Scion, have the place nuked, and bug out. As Doakes pointed out however, the Scion wouldn't deploy dropships unless the ultralisk was killed, the battlecruiser couldn't operate in the atmosphere, and he didn't trust the ship to make strategic nuclear strikes without taking them out as well. If they wanted to leave, they'd have to take the creature out themselves.
Torch Seven devised a plan to create a vespene gas bomb from the space supply at the lab. From there they would lure it into a ravine and collapse it on top of the creature. Torch Seven interrupted a communion ceremony held by Gerhardt van Rijn, and Sergeant Doakes lured the beast back to the ravine. The bomb was detonated on top of the creature, collapsing the ravine on top of it. Doakes sent Jouvert to investigate the wreckage to see if the ultralisk was dead, but the ultralisk came out of the rubble and sliced Jouvert in two.