Princess Luna is one night outside when she encounters an strange orb of energy.
When touching it, she is sent to a strange new world, battle-scarred and barren.
The last remains of the once-grand people now lives in underground tunnels, called the Metro.
Here, danger lurks behind every corner, mutated beasts and unknown phenonomenons.

And so, Luna must learn to adapt to the harsh Metro and if nessecary, to kill in order to survive.