Alien Agent Series by Pamela F. Service

In this first book of the Alien Agent series, we meet Zack, a normal kid with a crazy cousin, Ethan, who thinks he's an alien. But is Ethan really crazy? And why do the same bald, odd-looking fat guys keep reappearing everywhere the boys go?

Zack knows he's not a normal kid. He's really an alien agent-in-training, brought to Earth to help guide the planet into the Galactic Union. Aliens follow him to a ritzy summer camp, where he's hooked up with Vraj, a huge, dinosaur-like creature on her first-ever assignment. Their mission: To get back a bunch of alien Duthwi eggs that, if hatched, can harm Earth. Their problem: Lots of eggs, too little time, and those bad guys are still after them. So what's a young alien to do?

In the third book in the series, young Alien Agent Zack Gaither is sent to Mongolia to liaise with his fellow agent Vraj, whom we met in Camp Alien. Vraj's people, the Tirgizians, are exploring the area for evidence of dinosaurs, whom the Tirgizians believe to be their long-lost ancestors. Enter the Kaipa Kapa Syndicate, a mixture of bad guys, including the Gnairts who'd previously tried to kill Zack and Vraj... moreIn the third book in the series, young Alien Agent Zack Gaither is sent to Mongolia to liaise with his fellow agent Vraj, whom we met in Camp Alien. Vraj's people, the Tirgizians, are exploring the area for evidence of dinosaurs, whom the Tirgizians believe to be their long-lost ancestors. Enter the Kaipa Kapa Syndicate, a mixture of bad guys, including the Gnairts who'd previously tried to kill Zack and Vraj. The syndicate kidnaps the Tirgizians, and with the help of two local Mongolian kids, Zack and Vraj manage to free them and avoid being discovered. less

Zack’s back at work again, as an Alien Agent. His assignment: find an alien kid who hijacked a spaceship to Roswell, New Mexico. Sound easy? Not quite. Because Zack’s dad is going too. And he’s being chased by a man with a serious grudge against aliens. Can Zack find the missing alien and keep the truth from his dad while escaping the clutches of one Major Garrett? It’s all in a day’s work for Earth’s Alien Agent.