How to make things happen when you return hub after picking up item?

[Phoroneus]

I'd say the easiest way to do this would be to create a second, identical "hub" map. Once you pick up the item from DarkStorage, the leveldoor in DarkStorage leading back to the hub could be set to inactive and a duplicate in the same location could be set to active, sending you to "hub2" or somesuch instead of the original hub. This way you could constrain the player's ability to leave hub2 as well, or allow them to freely go to any of the other maps to escape (assuming that's what you want them to do).

Alternately, you can run an OnEnter function in the hub map's .hps that checks whether you have whatever item is in your inventory and triggers the events, though in order to make the changes permanent (i.e. they don't happen every time you come back to the hub, but their effects remain) I might still go with an alternate map.