Nobita Nobi is overwhelmed with nostalgia as he fondly remembers his adored grandmother. This prompts him to request Doraemon's aid in traveling back in time to see her once more. Upon reuniting with his grandmother, she expresses her desire to meet his future spouse, which Nobita agrees to out of loyalty. With the help of Doraemon, he embarks on a journey through time, only to realize on his wedding day that his future self is missing. Determined to fix the situation, Nobita and Doraemon set out on a mission to locate his future self and guide him towards happiness.