How the afternoon works depends on the Option you booked:
Plovdiv Extended Free Time: If you booked the base Plovdiv tour, you now have massive extended free time! Relax, dine in Kapana, or visit museums at your own pace. (Note: The shared bus will leave Plovdiv to conduct the "Grand Tours" and return later in the afternoon to pick you up).
Starosel OR Koprivshtitsa Grand Tours: If you booked a premium upgrade, you will re-board the bus and travel into the countryside to visit the Thracian Tomb of Starosel & Staro Zhelezare Art Village, OR the historic 19th-century town of Koprivshtitsa (depending on the day's specific route).