Season 7 begins Right after The Prunsel Fight,

Prunsel, an Big eyeball God has been defeated, he reveals that there will be enemies waiting for them, That once they enter to the door, they wont be able to return to PRESENT.

and to be aware of REDACTEDs and GLITCHES Around The World

Once a Monster Dies or Human does, they are PURGED From The World Permamently

So they must be alive in this Forgotten world as one mistake or rather one Death can Erase the entity.

you enter to INACCESSIBLE Rooms

your task is to reach to Final Room 338

However, On your way, you encounter similar enemies you met through your journey, Shadow Prunsel, And more!

As you went through the gauntlet of Enemies, you are meeting...An Omega Flowey?

However, This has Seperate Phases,

Phase 1 is The Chase

While Halfway, he will Progrressively get faster and chase you.

In Final Encounter on Final Door, You will have to face him after defeating Guardians.

After the Guardians get defeated, the door to final room is there

However after Failing the Omega Flowey Fight, you will have to Retreat and mostly, Be Prepared for what comes next.