The head engineer, a corrupt engineer who designed the bridge being built knowing it would collapse, is very impatient, rash, and selfish, and cares more about his reputation as the head engineer than the safety of others.
When Ash and his friends were going to Solaceon Town, they encountered the mayor and the head engineer, who told Isis that she needed to complete the bridge in time. Afterwards, he walked off, commenting about his reputation. The head engineer later returned when he found out that the bridge wasn't completed in time. He was overcome with rage and tried to make it himself with his own Pokémon, ignoring Isis's and Brock's reminder that Bibarel's help is needed to cut the stone quarry in the right shape. As a result, Bibarel attacked his Rhydon when it used Horn Drill. The head engineer then used his other Pokémon to beat up Bibarel to quickly get the job done.
The group, seeing what Bibarel was trying to do, battled the head engineer's Pokémon and defeated them. When the head engineer used his digger to dig through the quarry wall, a large rock that came from the expert stonecutter's Machamp knocked the digger over. Seeing that the head engineer was recklessly attacking the quarry, Isis and the expert stonecutter fired him, and the head engineer ran off along with his Pokémon.
The head engineer originally used his Rhydon in order to drill out rocks for the bridge, but the Drill Pokémon was quickly attacked and defeated by Bibarel. When Bibarel was cornered, Ash's Pikachu used Iron Tail to finish Rhydon off for good.
The head engineer sent his Aggron to attack Bibarel along with his Metang and Magmar. Bibarel was, however, easily able to dodge Aggron's attack. It was eventually defeated by Ash's Buizel's super-effective Water Gun.
The head engineer sent his Magmar to attack Bibarel along with his Aggron and Metang. After Aggron and Metang's attacks had failed to hit Bibarel, Magmar finally scored a hit. Thanks to this, Bibarel was cornered by all of the head engineer's Pokémon. However, all of them were eventually defeated Ash and his friends' Pokémon, with Magmar being taken out by Dawn's Piplup's super-effective Bubble Beam.