W Wish - Season 1 Episode 11 Senna's Truth

On the day Junna was separated by his real family, they were at an excavation site. Junna's father had showed him a dial he found and told him that the dial can grant a person's one strongest desire. Junna had wished to meet Senna, and Senna shared the same wish; as a result, the current world Junna lived in was born. In the present, Senna finds Junna at the park and reveals that when she and Junna were conceived, she died, but existed as a soul. Junna has always felt her presence, so that was why he knew of her existence. Tomo explains that since Junna and Senna's wish was granted, the dial has to take a compensation to create the world, which was the death of his parents and Haruhi living in Junna's dreams. Surprisingly, Haruhi was not supposed to exist in this new world, but because Junna had abandoned her in his dream world, she came searching for him, becoming his childhood friend in this world. Tomo informs Junna that because Haruhi and Senna cannot co-exist in the same plane, the balance between the worlds are starting to collapse, explaining the fog that has emerged in the city. She gives Junna two choices: stay with his current lifestyle with Senna or return to his old one with his parents and Haruhi.