Transplant or relocation shock

What's happening

Croton is famously dramatic about any change in its environment. A new pot, a new room, a different light level, or even the trip home from the store shifts the conditions its leaves were grown for, and it responds by shedding leaves while it adjusts. This is stress, not death — the plant is rebalancing how many leaves it can support in the new spot.

How to fix it

Resist the urge to do anything drastic. Settle the plant in one bright, stable location and leave it there — don't keep moving it to find a better spot, which only restarts the shock. Keep watering consistent, hold off on fertilizer for a few weeks, and give it bright indirect to some direct light. New leaves should appear within a month or two as it acclimates, so be patient and let it recover undisturbed.

This is general guidance based on common symptoms; individual plants vary.