Help thinking of a word please!

[IDidntWearASmileToday]

I'm writing a fictional book and I'm after a word but just can't think of one to fit.
What would you call an object you are responsible for/holding.
Someone is driving so you're looking after their item - I don't want to call it by name in the first instance as it just doesn't fit right with the rest of the sentence...
...hope this makes sense - thanks!

'Precious cargo'

Charge?

Protecting?

‘charge’?
Lexico:
Charge
Noun
3.1count noun A person or thing entrusted to the care of someone.
‘the babysitter watched over her charges’
www.lexico.com/definition/charge

Handling?

Depends on context and what it actually is but do any of these make sense: Prize, charge, quarry, offering, bounty, bequest

‘Item in his/her temporary custody’

Ah brilliant, thanks everyone - the word I was trying to think of was charge but I'm going with cargo instead. Thanks again for all of your help!