A bunch of memories
Life is like a box of sweet & sour memories. Every memory has something related to it, doesn't it? Has it ever happened with you that once you go down to the memory lane, it's difficult to come back from it. There is a moment of joy, happiness & nostalgia when we go through some old memories. Memories are very beautiful. It takes us back to some old stories which gives a different kind of happiness. Memories is something which no one can take away from us.
Same is happening with Naina while she goes through her bunch of old memories.