What gandalf does, turn by turn. CHARACTERS_ACT runs one step of a character's script each turn it can, and a step is an action the character tries as if it had typed it: RUN, TAKE, GIVE TO. A step that names nothing acts on whatever fits.

First comes the script table: one entry per script, a key and the script's address. Key 0 is an ordinary script -- the ones a character wanders between, picked at random by a 'switch at random' step. Any other key is an action code, and that script is the character's reaction when that is done to it: attacked, given something, captured.

Then the scripts, one step to a line. A step's first byte says what it is: its low four bits $00-$03 an action with objects (or, $01 and $03, a routine to call), $04 an action with none, $0E go to, $0F switch at random, $0C switch to a reaction. $10 added means an address follows, where the script goes on if the step is refused; $20 that the step is used up once it works (SCRIPT_DO zeroes its first byte); $40 that an order from the player cannot interrupt it. So $14 is an action with no objects, with somewhere to go if it is refused. The Characters page has every script written out.