The Fourth Protocol

01 · Episode one

Forty days at Cencom

Episode one runs on a clock. A day lasts 14,400 frames, 4 minutes 48 seconds on a European machine. The game gives you 40 days to find who is passing NATO's papers on.

The clock is the raster interrupt, which the video chip raises once a frame: day_clock ($5C38) counts the frames and ends the day when the count reaches 14,400. The calendar starts in June and turns to July with a picture of an L drawn over the N of JUN (pic_calendar_l).

Everything that happens is an event in one of four lists, from $1000 on: the story's memos, the reports, the watchers' findings and the telephone calls. Each list has eight places for each of 41 days. A choice you make, an option in a memo or an answer on the telephone, puts the next event a few days ahead (schedule_in).

Your prestige starts at 500, and the game ends if it falls below 50 (add_prestige). Prestige also sets how many watchers you may put on your suspects: a tenth of your prestige, plus 50, which makes 100 at the start (watcher_allowance).

Watchers are how most of the story moves. SURVEILLANCE takes a surname and up to 25 watchers for it. Each new day, for each name with watchers, the game picks a number from 1 to 50, and the watchers find something if there are at least that many of them (watcher_chance, $5DC6), so 25 watchers succeed about half the time. What they find depends on the name's day, the last byte of its record. Before that day, or while it is 0, the find is a sitrep saying that nothing happened (daily_surveillance). The game knows 16 names (target_records), and a surname it does not know becomes a target whose day is always 99, so its watchers never find anything.

Memos, reports, sitreps and calls wait in four trays. ACT runs a memo's or a report's routine, once. DELETE on a memo not yet acted on runs it first, so deleting a memo has the same consequences as acting on it (next_memo, $5813). A call rings for 1,920 frames, about 38 seconds, and one left ringing is lost (call_timer). Each tray holds 48 items. A 49th stops the game: post_item ($5EB3) prints DEBUG ERROR and Office stack full, then cycles the border's colour for ever. Watched names bring sitreps every day, most of them saying that nothing happened, so they need deleting.

02 · The story-lines

Every story-line starts on a fixed day, then waits for you

The same memos arrive on the same days in every game. After its first memo, a story-line moves only when you do: watchers on the right name, an answer to a memo or a report, or a number dialled. Choose a story-line to see its steps.

Two things are left to chance: the code word for Blenheim, picked as the episode starts, and the day watchers find something. Everything else is fixed, both the day each story-line starts and what each answer leads to.

The ASSESSMENT icon shows progress as a percentage (show_progress), and the ending screen gives it again as YOU HAVE COMPLETED so many % OF THE GAME. The best answers in every story-line add up to exactly 100. Only the NATO leak can win the game. The others add progress and prestige, and prestige keeps the game going and pays for watchers. Most story-lines also have a wrong answer that costs prestige, and two go on costing it. Once memo 38 has been acted on, memo 40 and report 15 come back every day, for 50 prestige each time, for as long as Maras has watchers. Thorn's calls cost 10 each until Bracton is dealt with.

03 · The NATO leak

Catching the spy, step by step

Only one story-line wins the episode. It cannot begin before day 18, each step waits on the one before, and one unanswered telephone call loses it.

Memo 8, on day 3, says that photocopies of five top secret NATO papers have come through the post. Blenheim has the rest. Files PAPER 1 to PAPER 5 give each paper's circulation list as initials, and files CABINET, FOREIGN and MOD list each department's staff, with a star for those who can use a photocopier. Only the Ministry of Defence saw all five papers. Five of its staff are on all five lists and have a star: T Allen, D Faulkner, F Janes, R Night and A Sopwith. Allen, Faulkner and Sopwith are among the 16 names the game knows, and watchers on Janes or Night never find anything.

Faulkner's watchers find nothing before day 18 (init_faulkner), so a player who watches him from the start sees two weeks of sitreps saying that nothing happened. From day 18 the case runs through the Pizza House and its owners, the Genovese brothers, whose name is only in the PIZZA file at Blenheim, then a tape and the voices of the nine customers on the delivery list. The voice prints under report 3 point to the name Sir Anthony Plumb wants on the telephone, NILSON. His call rings once. A call left ringing is lost, and the routine for call 12 missed is an RTS, an instruction that returns at once, so the call never comes back and the case cannot be won.

Sweden tells the story behind the name. Nilson's army file leads to the files on a patrol he led in Gaza, where his sergeant, Torsen Stenberij, was reported killed. The commander's report says that the two were so alike that they were often taken for brothers. In Borgafjall the police say that Nilson's father Holmar died in a climbing fall, and Lars at the climbing shop says that he went up with three strangers who came back without him. Holmar's sister Anna moved to Storuman, and among his things she keeps some old exercise books with a smudged, inky fingerprint, the proof Plumb wants. Plumb's answers are FAULKNER, SWEDISH, NILSON, STENBERIJ, FINGERPRINT and GAZA, and DEREK, STIG and TORSEN will do for three of them. A trip home without the fingerprint costs 100 prestige, and memo 27 never comes again, so Sweden cannot be visited a second time.

Six right answers start a countdown of ten days, and its end wins the game (plumb_questions, $501B). Day 41 wins as well while the countdown runs, so the answers may come as late as day 40, and day 41 without them loses. With every find on its first possible day and no detour in Sweden, Plumb can be answered on day 30. Each find is a roll of the dice, though, so the days from 18 to 40 go quickly. The winning memo, from Sir Nigel Irvine, gives a new password: 10 190 216 277 358. Nothing in the game asks for it. The first lift in episode two wants ASPEN, a word of five letters, and the one-time pads that would turn the five numbers into letters are not in the program.

04 · Building 17

Building 17's locks

Memo 28 asks you to secure Building 17. building_17 ($7BE4) draws its basement and then its ground floor, and you choose a lock for each door.

As you leave, judge_locks ($7C3F) gives its verdict in memos, most of them the next day. Lock doors below to see what it says. A building that fails brings memo 32, a serious breach, every time. The code was meant to bring memo 31, a break-in, one time in 99 instead, and a slip in it means memo 31 never comes (Discoveries).