"Ted, it's really stacking up against you here, mate."
Does this mean that things are going unfavorable for Ted??
Situation: Ted is an suspect of a murder case and every evidence indicates he is a criminal. And a detective said this to Ted.
"Ted, it's really stacking up against you here, mate."
Does this mean that things are going unfavorable for Ted??
Situation: Ted is an suspect of a murder case and every evidence indicates he is a criminal. And a detective said this to Ted.
It's stacking up against you
...is essentially a "dummy it" usage (where it doesn't refer to anything in particular, just the surrounding situation / context in general (cf It's good to be alive!, It's raining, etc.)
The [phrasal] verb to stack [up] could usually be replaced by to pile [up], to accumulate, etc. But note the significance of immediately-following against - this strongly implies that what's happening is contrary (to you, your best interests). Which isn't always the case, as shown by...
...things are stacking up for you in beneficial ways. ("Your Daily Horoscope" by Ebox Mauritius)
It should by now be obvious that it's really stacking up against you here means the current situation is looking increasingly bad for you.
But I wouldn't have posted this answer purely to confirm OP's suspicion that it means things are going unfavorable for Ted (which should be unfavourably / unfavorably anyway).
I don't want to imply criticism of OP for failing to follow the implications of the word against, or to consider the same construction with alternative "synonyms" for to stack [up]. But I hope at least some users here might take note that even though it's notoriously difficult for non-Anglophones to actually use prepositions correctly in all contexts, you can often make use of the specific prepositions used in contexts where you're not sure about the meaning of other words nearby (in OP's specific case, by noting that against = not in favour).
evidence or a situation is said to stack up against someone in English.
This means: to form a pile of evidence or information that is not good for a person; it is against them.
Stack up can also have a more general meaning in AmE: to measure or compare.