In the original movie, drama was drawn out of the fact that time is immutable and all the attempts of Cole to change the past are destined to fail.
In the tv show this also seems to be the case most times, except in one episode where Cassy is killed the future changes dramatically and is later fixed by Cole. A minor example is in the first episode where Cole damages the glass of Cassies clock and the clock from the future follows to show the damage.
While it is a common trope in time travel stories to have a timeline that "resists" changes and behaves like immutable and predestined (and even allows for bootstrap paradoxa) and you have to realy try very hard to change it, it seems to me like this is handled inconsistently.
The clock example seems not logical to me. In most other situations things that Cole does later in his timeline (but further in the past) already happened. So in the case of the clock the scratch should have been on the future clock already. He used this to convince Cassy. And everything he does later is based on this. If he wasn't able to convince her, everything would have been very different.
But how can things he does later in his timeline, that depends on convincing Cassy be predestined and already done in the timeline, while the convincing of Cassy with the clock was not predestined (otherwise the scratch would have already been on the future clock) and needed a paradoxon?
How can predestined events be causaly dependant an not predestined?
Im at the end of the first season now. Are the mechanics explained later in the show?