Jenceslav

Scenarios (e.g. Attack on Sandpoint) should not be dependent on any other scenarios, but adventure rewards (a set of scenarios, e.g. Burnt Offerings) can be received if and only if the character successfully finished each scenario in it (i.e. Attack on Sandpoint to Thistletop Delve). That is the reason for the Completion tab in the Character management window...

Hello, I am afraid your problem is that you ran into a long-known but still not corrected bug. If you use any action of card (Cape of Movement, Haste, Stride) to move a character to the Temple location (forcing you to discard card/s when moving there), the game will become stuck. I usually do not use such spells to move characters, so I never observed it myself.
If you can forfeit the scenario (Click on the cog/wheel on the bottom left and choose forfeit - i.e. give up the scenario with the possibility to try it again from the beginning), do so. If you cannot forfeit, contact the game support and tell them this problem + your PFID number (long hexadecimal number found in the settings of the game) - your id is not enough, unfortunately.