Lattice Netrunning — GURPS hybrid (GM spine)

Game: Orion Corridor — 2277 · Setting: Khesret system · Rules: GURPS 4e at the table. System: GURPS engine + Shadowrun procedures + Cyberpunk meat pressure.

Naming (do not collide)

Runner slang: lattice diver, overwatch, ghost thread, host, ICE.

Design goal

Blend Shadowrun (programs, IC, overwatch, host topology, biofeedback), Cyberpunk (architecture levels, meat vulnerability), and GURPS 4e (skills, Quick Contests, injury, Techniques) without replacing GURPS combat.

1. GURPS stays the engine — attributes, skills, contests, wounds, FP/HP.
2. Shadowrun programs → GURPS Techniques defaulting to Computer Programming.
3. Shadowrun scene procedure — overwatch + legwork + on-the-fly hacking.
4. Cyberpunk pressure — diver’s body is a fixed target; team holds the room.

The three-track table model

Every Lattice scene runs up to three parallel tracks. Most rounds only one or two are active.

MEAT TRACK          LATTICE TRACK         ASTRAL TRACK (optional)
(GURPS 1-sec)       (Pulse or abstract)   (if awakened PC)
─────────────────────────────────────────────────────────────
Team combat         Diver in host         Mage on astral overwatch
Social / stealth    Overwatch defender    Spirit probe (separate)
Driver waiting      Legwork (extended)    —

When to engage each track

GM rule of thumb: One diver → abstract Lattice turns (one action per meat turn or 3-second pulse). Full table invested → host zone map (3–7 zones).

Access modes

Khesret tone: hot sim exists; black clinics and corp liability make cold sim common for amateurs.

Core GURPS skills

Do not use GURPS Hacking as a single skill — use Computer Programming + Techniques below.

Optional advantages

• Digital Mind or Compartmentalized Mind — Lattice scenes only (−50% Virtual Reality)
• Resistant (Biofeedback) — sim rig filter quality
• Security Clearance / Access Credentials — legal lattice keys

Cyberware is optional in Khesret — jacks are gear, not character tax.

Programs = Techniques

Each program is a Technique defaulting to Computer Programming −N. Roll Technique; margin = effect.

Running programs: Armor + Analyze = two actions per pulse unless deck has multitasking edge.

Host topology

Sketch 3–7 zones per host. Example Meridian Legal Relay:

[Public Lobby] — [Security Queue] — [File Vault] — [Admin Core]
      │                  │               │
   Patrol ICE        Scramble ICE    Black Hammer ICE

Each zone deeper = +1 noise or −1 overwatch reach.

ICE and personas (summary)

Build ICE like minimal NPCs — see Three-Plane Pools & Black ICE for damage and Black ICE kill chain.

Overwatch holds reactions: Biofeedback Filter, Track, Attack vs traced ICE.

Scene procedures

1. Overwatch

1. Team declares physical plan (meat track).
2. Diver declares entry point (Sniffer, credential, physical tap).
3. Overwatch sets posture: Passive (Analyze) / Active (Track+Filter) / Aggressive (Attack if traced).
4. Run meat round; diver gets one Lattice action per round (or 3-sec pulse).
5. On alert, ICE spawns or security checks meat.

2. Hacking on the fly

1. Task difficulty modifier −0 to −6.
2. Extended test — Programming or Technique; one roll = one risk tick.
3. Each failure: +1 heat; third failure = ICE or meat security.

3. Matrix legwork (prep)

1. Days = Research or Browse extended tests.
2. Success = clues for meat team.
3. Failure = false lead or heat on future dive.

4. AR micro-actions

• Computer Operation for public Lattice data.
• Contest vs Spoof if target hides.

Khesret canon hooks

Tone: cool, wry, tired — not Tron neon unless the host demands it.

Session prep checklist

1. Host name + 3 zones + one secret
2. ICE tier + one data bomb optional
3. Meat complication (who guards the diver?)
4. Overwatch role assigned
5. Legwork clue if prep happened
6. Heat clock 0–6 (optional)

Scope lock

• No Shadowrun initiative pass import
• No Lattice-only sessions replacing guns/combat
• No merged Astral + Lattice plane
• No mandatory cyberware
• No GURPS Hacking single skill

Companion doc: Three-Plane Pools & Black ICE