Plunger (Reckless Hand) build

The Plunger axis (Reckless Hand) activates doubling where basic strategy says don’t. Anchored opposite of wedding_ring (which rewards basic-strategy-aligned even-total doubles).

Charm	Tier	Trigger	Effect
The Open Hand	uncommon	onWin (post-double)	hard-12-16 OR soft-19+ → ×1.5 final mult
The Last Coin	rare	onWin (post-double)	hard-17+ → +10 mult, +bet chips (4× total payout)
The Doubled Wager	mythic	onWin (post-double)	each reckless double-win banks +25 chips, caps at 6 fires/campaign
The Vow of the Plunger	rare/drawback	onResolve	sets any_double_allowed + bust_penalty_factor=2 flags

How “reckless double” is detected

Pre-double total is computed via the _handValueAtPrefix(cards, 2) / _isSoftPrefix(cards, 2) helpers — doubling adds exactly one card so the first 2 cards carry the moment-of-decision state.

Soft/hard distinction lets Open Hand and Last Coin partition cleanly:

Pre-double total	Owns it
Hard 12-16	The Open Hand
Soft 19+	The Open Hand
Hard 17+	The Last Coin
Doubled Wager	All of the above

The thesis

Chip-aggressive players push a second coin onto the table when they shouldn’t. Worked example: Open Hand on hard 14 vs dealer 6 → doubling becomes cascade-correct per chip wagered (~73 EV vs basic-strategy-recommended hit’s ~25 EV).

Vow of the Plunger

Drawback-negotiated. When held:

• vow_of_plunger:any_double_allowed: true — NightRunner relaxes the double-action gate (any 2-card hand may double, plus mid-hit doubling if the engine path supports it).
• vow_of_plunger:bust_penalty_factor: 2 — doubled busts cost 2× the normal capital settlement.

Composition with Long-Game

A reckless double-win on hard 14 with one hit before busting is not a thing (you can’t double after hitting in standard rules — Plunger Vow lifts that, but most plays are pure 2-card → 3-card). So Long-Game hitCount=1, factor 1.3.

archetype 2.0 × 1.3 (long-game)        = 2.6 mult
× 1.5 (Open Hand if pre-double 14)     = 3.9 mult
× 20 chips (5 + 6 + 9 = 20 final)      = 78 score base
+ Doubled Wager bank +25 if not capped

Dealer’s voice on Plunger play

“A coin you should not have laid. He counts it twice anyway.” — Doubled Wager fires

“You doubled where the books said no. The books are quiet now.” — engineMoment, post-Plunger cascade

“He laid down a coin he could not afford. The cup tipped his way.” — Last Coin fires on hard-17 win

Where this lives

• lib/sim/arcana/arcana.dart — TheOpenHand, TheLastCoin, TheDoubledWager, TheVowOfThePlunger.
• test/sim/plunger_build_test.dart — 19 unit tests.

Engine prereq notes

active_doubled flag already exists for wedding_ring. The Plunger Vow’s any_double_allowed and bust_penalty_factor flags are NightRunner-side and ship as data primitives; engine wiring follows in Phase 5 recalibration.