The Hiker Trio are three separate guys that look very similar. They have blonde hair, wear the same outfits and carry a big backpack.
The Ultra Guardians visited Wela Volcano and concluded that the magnetic anomalies were caused by the Graveler and Geodude because they were chased out of their normal eating areas by rock hunters looking for Spark Stones.
Lusamine suggested that Wela Volcano needed more patrols but would be too much for Officer Jenny to handle by herself. The Golem appeared and overheard the conversation and wanted to be caught by the Hiker Trio's when they said they were the perfect people for the job as they knew the area like the back of their hands.