When I ran Into the Past it was a series of battles using tactical maps. I “borrowed” the basic setup and idea from the encounters of the same name from Revenge of the Giants. Here is the layout of Xoud’s Laboratory with each monster key. These were tough encounters for my party of four level 8 characters as they couldn’t take a long rest (it would immediately take them back to the present day) and the encounters are setup using 4e monster numbers which are much larger than 5e. But some clever play and avoiding a fight with Xoud saw the party succeed. If you are interested in the environmental details and tactics I recommend grabbing Revenge of the Giants. Though the monsters are designed to compliment each other so how they play works out naturally when you use their abilities.
Technic League Compound, Starfall (AR 4701 AR)
First Level – Entry Hall
Characters teleport in and appear in the summoning circle. Their goal is to retrieve the skymetal from the two secret rooms. The guardians activate when the party either enters a secret room or trigger/disable the lighting cage trap. K represents a Knight, D represents a Destroyer (I reduced this to 1 destroyer instead of the 2 shown) and F is a Thunder Priest. The room across from the teleporation circle has four partially contructed/refurbished gearsmen and a myrmidon.
Second Level – Library and Workshop
This larger area has two encounters. One in the workshop (on the left) and one in the Libray (on the right). The first area has a locked door and the two gargoyle statues are traps that will trigger if the doors are forced open or atempt to unloc with Theives Tool and fail. Gargoyles spit out gouts of fire. In fact there are two other traps as well as the characters head to the third level and confront Xoud. The first is a spiked-floor trap and the second, larger one, is a fire cage preventing further movement. The both rooms have large windoes with views of Silver Mount, Starfall and the rest of the Technic League Compound. The Workshop also has a disecated auromvorax on the table and the Library has a rare book detailing all the Technic Leagues current knowledge about Silver Mount and a number of other technological ruins written by Xoud himself (valued at 5,000 gp). The map shows the following creatures – B is a Boneclaw, F are Guardian-Skulls, S are the Hunter-Killer – “Bastion Class” robots N is the Prototype Robot Apprentice and W the Smoke Archons. The skymetal can be found in the secret room filled with statues to the south.
Third Level – Starforge
This is another trap filled map. Xoud is marked by the A on the map. He stands near the
Starforge a machine that can convert and refine starmetal directly from the wreckage of the starship. The two magic circles represent two holographic generators. The hardlight holograms spawn from these two machines. They must be disabled to stop them. Each tile marked with a T is a ooze trap which will restrain and slow down the party as they advance. The causeway area is open to the sky and marked by sigils. These trigger an arcane cage designed to stop/delay invaders. The starforge can be raided directly for its skymetal. Alterntively a if they can convince Xoud to parley (This requires 8 successes before 3 failures: Any Charisma based skill (DC 20), History (DC 10), Insight (DC 15)). If the challenge fails, Xoud calls them thieves as he launches an attack.