Scene of Clannad (After Story) from episode 21, Tomoya Okazaki was walking with his daugther Ushio Okazaki to the train station. Tomoya kept asking Ushio if she wanted something, she always responded that she wanted to go on another trip with him, but she was ill (name of the illness is never mentioned). Tomoya wanted to grant her that wish.引用元： Youtube
Link explaining the ending:
Move you mouse on the empty blank space with the vertical yellow line, text explaining it all will appear.
This other link helps explain the "light orbs" and how wishes are granted:
Listen to this beautiful Clannad-inspired music, made by AlphaOrchestra!
Listen to the soundtrack used in this clip
Footage: Clannad - After Story episode 21
Song: "Snowfield" from the Clannad Original Soundtrack (OST)
Disclaimer: I do not own the audio nor footage in this video. No copyright infringement intended. Everything belongs to their respective owners.