Nobita's Time Heist

Upon waking up, he finds that technology has regressed to sixty years ago. In the town of Tsukimidai, all memories of Doraemon have vanished without a trace, along with the regression of time.
After many twists and turns, Nobita and his friends learn the truth: an unprecedented, massive, and time-spanning war is unfolding, and its target is the future where human technology is booming. The dominoes hidden in the past have already fallen, and are about to form a monstrous wave that will engulf every era of humanity.
The only clue is a snapshot that also spans time.
On September 19, 1492, at the center of a vortex of spacetime turbulence, the Time Police captured a photograph of the back of a blue nursing cat-shaped robot.
Taking this opportunity, Nobita and his friends are drawn into a time-traveling heist. As they uncover more and more clues across different eras, a massive conspiracy gradually comes to light.