OVER A CUP OF COFFEE : leap promo : SEPARATED BY LOVE (season 2)

Leap promo:
SEPARATED WITH LOVE

“Sanam re” tune was playing in the back..
Background words are heard:
“3 years.. I have not seen him.. Hope he is doing ok..though I am miles away from him.. Yet he lives in my heart.. Close to me..”
The snow drops fall upon the beautiful Washington park. A girl covered in furry jacket.. Is seen playing with the snow..A man is seen walking towards her hugging her from behind.. Kissing upon her neck.. The girl gets uncomfortable.. But does not say anything seeing a tiny girl stand before them..
“Papa loves mamma”the girl says chukling. And runs into the car…
The girl pushes the man…her face is revealed.. It is Sona..
“Don’t even think…” she says pointing towards the man.. It was Ritwick.. He holds her fingers..
“My love.. Why get so angry? Dev –”
“Don’t even take his name by your dirty mouth–”
Ritwick glares at her angrily as she walks inside.

Dev is seen walking with barriers in a dungeon.. It was dark.. He does not remember anything… shocks after shocks was given to him.. That he does not remember who he was.. He walks around shabbily and tired..
“4621”
That was his identity now.. He chuckles hearing that number..
Ishwari looks on tearfully, as Asha supports her..

The promo closes with the following lines from “Ae dil hai mushkil”…
“Ek tarfa pyar ki taqat hi kuch aur hoti hai…auron ke rishton ki tarah yeh do logon mein nahi bat’ti.. Sirf mera haq hai ispe”… As the tune of ADHM plays in the background.

Will the destiny bring the two together again??
What made Sona leave Dev and stay with Ritwick?? How did Dev become mentally unstable?? Is this a conspiracy?? Then of whom??