Yoko is a 22nd-century reporter for the organization Private Eyes. Her assignments focus on investigating major criminal activities, primarily tracking the elusive villain Mr. X, responsible for destroying satellites and space shuttles. She operates with an android partner known as Beat or Pete, who functions as her photographer, bodyguard, and cameraman. This android possesses enhanced combat capabilities activated via a specialized compact device operated by Yoko.

Leading the investigative duo, Yoko directs their pursuit of Mr. X to his hideout within the Technoland amusement park, driven by determination to expose his crimes. During the confrontation at Technoland's Rainbow Tower, Mr. X captures Yoko, holding her hostage and requiring intervention from her android partner. The android ensures Yoko's safety by destroying the programming of the tower's central computer, thwarting Mr. X's escape plan.

This investigation represents Yoko's primary documented assignment. Her journalistic work centers on uncovering truths behind dangerous criminal operations, placing her in high-risk situations where she counts on both her own resolve and her partner's unique capabilities.