Fall (squarely) on (someone's) shoulders informal verb phrase
If something falls (squarely) on someone’s shoulders, it is the responsibility that one have to take.
When my parents passed away, taking care of the kids fell on my shoulders.
When the director is away, the management of the company falls on my shoulders.
Today is a busy day. Linda is sick, so all her work falls squarely on my shoulders.
I can't understand why all the blame fell on Jin's shoulders.
Being looked after or protected by someone
It is used to tell someone that it is time for them to take action or make a decision.
To give someone a particular responsibility or duty
Used to indicate the responsibility belongs to someone, normally a negative one.
The verb "fall" should be conjugated according to its tense.