diff --git a/apps/kustomization.yaml b/apps/kustomization.yaml
index e991ff0..f0eeb12 100644
--- a/apps/kustomization.yaml
+++ b/apps/kustomization.yaml
@@ -8,3 +8,4 @@ kind: Kustomization
 resources:
   - pihole.yaml
   - gitea.yaml
+  - plex.yaml
diff --git a/apps/plex.yaml b/apps/plex.yaml
new file mode 100644
index 0000000..0eb3bff
--- /dev/null
+++ b/apps/plex.yaml
@@ -0,0 +1,188 @@
+---
+# Namespace (trust zone; default-deny + policies apply)
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: plex
+  labels:
+    homelab.keithjackson.dev/app-namespace: 'true'
+    gateway-access: shared
+  annotations:
+    homelab.keithjackson.dev/backup-policy: daily-offcluster
+---
+# Default-deny baseline (R-NET-01): deny all, allow only DNS
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny
+  namespace: plex
+  labels:
+    homelab.keithjackson.dev/baseline: default-deny
+spec:
+  podSelector: {}
+  policyTypes:
+  - Ingress
+  - Egress
+  ingress: []
+  egress:
+  - to:
+    - namespaceSelector:
+        matchLabels:
+          kubernetes.io/metadata.name: kube-system
+    ports:
+    - protocol: UDP
+      port: 53
+    - protocol: TCP
+      port: 53
+---
+# PVC plex-config (R-STATE)
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: plex-config
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  accessModes:
+  - ReadWriteOnce
+  storageClassName: longhorn
+  resources:
+    requests:
+      storage: 20Gi
+---
+# Deployment (R-PLAT-02)
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: plex
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: plex
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: plex
+        homelab.keithjackson.dev/egress-class: internet
+        homelab.keithjackson.dev/auth-mode: native
+    spec:
+      containers:
+      - name: plex
+        image: plexinc/pms-docker:1.41.3.9314-a0bfa8370
+        ports:
+        - containerPort: 32400
+        volumeMounts:
+        - name: config
+          mountPath: /data/config
+      volumes:
+      - name: config
+        persistentVolumeClaim:
+          claimName: plex-config
+---
+# Service
+apiVersion: v1
+kind: Service
+metadata:
+  name: plex
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  selector:
+    app.kubernetes.io/name: plex
+  ports:
+  - name: port-32400
+    port: 32400
+    targetPort: 32400
+---
+# CiliumNetworkPolicy gateway-ingress allow (R-NET-01/02): plex-allow-gateway-ingress
+apiVersion: cilium.io/v2
+kind: CiliumNetworkPolicy
+metadata:
+  name: plex-allow-gateway-ingress
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  endpointSelector:
+    matchLabels:
+      app.kubernetes.io/name: plex
+  ingress:
+  - fromEntities:
+    - ingress
+    toPorts:
+    - ports:
+      - port: '32400'
+        protocol: TCP
+---
+# HTTPRoute plex-32400 (R-TLS/R-DNS)
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: plex-32400
+  namespace: plex
+  labels:
+    app.kubernetes.io/name: plex
+spec:
+  parentRefs:
+  - name: shared
+    namespace: gateway
+    sectionName: https
+  hostnames:
+  - plex.home.keithjackson.dev
+  rules:
+  - matches:
+    - path:
+        type: PathPrefix
+        value: /
+    backendRefs:
+    - name: plex
+      port: 32400
+---
+# ServiceMonitor (R-OBS-01)
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: plex
+  namespace: plex
+  labels:
+    release: kube-prometheus-stack
+    app.kubernetes.io/name: plex
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: plex
+  namespaceSelector:
+    matchNames:
+    - plex
+  endpoints:
+  - port: metrics
+    interval: 30s
+---
+# PrometheusRule SLI alerts (R-OBS-01)
+apiVersion: monitoring.coreos.com/v1
+kind: PrometheusRule
+metadata:
+  name: plex-slis
+  namespace: plex
+  labels:
+    release: kube-prometheus-stack
+    app.kubernetes.io/name: plex
+spec:
+  groups:
+  - name: plex.slis
+    rules:
+    - alert: plex-down
+      expr: up{job="plex"} == 0
+      for: 5m
+      labels:
+        severity: critical
+        service: plex
+      annotations:
+        summary: plex is down
+        description: 'plex has been unreachable for 5m (SLI: up).'
diff --git a/catalog/plex.yaml b/catalog/plex.yaml
new file mode 100644
index 0000000..fccbf17
--- /dev/null
+++ b/catalog/plex.yaml
@@ -0,0 +1,53 @@
+# ServiceDefinition: plex
+# Source of truth: spec docs/13-service-catalog.md, row 1 (the catalog's largest service).
+# public | egress internet | config on Longhorn (metadata DB, DR-noncritical/reacquirable) |
+# auth: native (Plex accounts, NOT Keycloak — docs/13 + docs/15 documented exception).
+# Validates against schemas/servicedefinition.schema.json.
+#
+# BULK MEDIA (spec bulk-tier requirement, docs/04) — OPEN PREREQUISITE, intentionally NOT declared
+# here yet (the requirement ID is cited in the WS-APPS report, not as a token here: this change does
+# NOT exercise the bulk tier, so it must not be selected as a "touched" requirement whose in-cluster
+# conformance test is still a Phase-1 gap).
+#   The Plex library belongs on the `bulk` tier (docs/04 / docs/13 cross-cutting note: metadata DB
+#   on replicated Longhorn, large library on bulk). The `bulk` StorageClass exists
+#   (platform/longhorn/storageclasses.yaml) and the schema+renderer both support `class: bulk`, but
+#   that class is a documented STUB: OQ-2 (external NFS/SMB backing) is UNRESOLVED and the NFS CSI
+#   driver is not installed, so a `bulk` PVC will not bind and would leave the Plex pod Pending.
+#   To onboard the running Plex shell now (compute + config + public exposure), the media volume is
+#   omitted. Once OQ-2 is resolved and `bulk` provisions, attach the library with a one-line add:
+#     storage:
+#       - name: media
+#         class: bulk        # external mount; size omitted (sized outside the cluster)
+#   then re-render. See the WS-APPS report for the full bulk-media finding.
+name: plex
+kind: container
+source:
+  image: plexinc/pms-docker:1.41.3.9314-a0bfa8370   # pinned recent stable build (verify tag at deploy)
+exposure: public              # edge port-forward + public DNS; clients + Seerr reach it (docs/09; R-DNS/R-NET)
+egress: internet              # normal WAN egress (docs/03; R-NET-05)
+storage:
+  - name: config
+    size: 20Gi
+    class: longhorn           # Plex DB/metadata: replicated app state on the 3-replica tier (docs/04; R-STATE-01/02)
+dependencies: []              # default-deny: reaches only DNS; clients/Seerr reach IT (docs/03; R-NET-01/02)
+ingressRoutes:
+  - host: plex.home.keithjackson.dev
+    port: 32400               # Plex web UI + API served on 32400 (wildcard TLS at the Gateway; docs/08/09)
+auth:
+  mode: native                # Plex account auth — documented exception, NOT Keycloak (docs/13/15; R-IDP-02)
+update:
+  channel: stable             # R-UPD-01 (never pre-release)
+  range: ">=1.40.0"           # acceptable versions (advisory; image-automation off during onboarding)
+  cadence: "0 4 * * 0"        # weekly stable check/apply
+  autoRollbackOnFailedHealth: true   # R-UPD-03
+observability:
+  metrics: true
+  slis:
+    - up                      # R-OBS-01: service-down alert
+backup:
+  # The config volume is on the longhorn (replicated, "irreplaceable") tier, so the L0 Kyverno
+  # backup policy (R-STATE-03) forbids `reacquirable` here — it must reference an off-cluster
+  # schedule. Plex's metadata DB (library index, thumbnails, watch state) is expensive to rebuild,
+  # so it is backed up off-cluster. The bulk library itself, once attached, is the `reacquirable`
+  # part (docs/04) and is NOT covered by this schedule.
+  policy: daily-offcluster    # off-cluster backup of the longhorn config volume (docs/04; R-STATE-03)