たどりついた手紙 is a Weiß Schwarz card from Summer Pockets SMP/W60-045. Compare listings from Singapore Weiß Schwarz sellers on CardJio, then jio them on WhatsApp.
Brainstorm Put the top card of your deck into your stock. Flip over three cards from the top of your deck, and put them into your waiting room. If there is a climax revealed among those cards, put this card into your stock.