Obtained: Speak to the little Upset Girl across from the Shibuya Idolasphere.
After each time you find a stamp card, head back to the girl to turn them over and receive a clue where the next one is located. The first stamp card is located on the north side of Toubo Rooftop. The second one is located in Harajuku on the ground in front of Crepes Dia. The last stamp card is located to the far west of Hee Ho Mart near the map transition. After you return all the stamp cards to the girl, the request will complete.
Reward: Pharmacy Beads