diff --git a/plugins/GroupDetails/GroupDetails.css b/plugins/GroupDetails/GroupDetails.css
new file mode 100644
index 00000000..fa1d4473
--- /dev/null
+++ b/plugins/GroupDetails/GroupDetails.css
@@ -0,0 +1,20 @@
+.group-card .card-popovers .gd-stat {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  min-width: 4.5rem;
+  padding: 0.2rem 0.45rem;
+  font-size: 0.9rem;
+  line-height: 1.1;
+  color: var(--text, #d5dbe3);
+  opacity: 0.95;
+  white-space: nowrap;
+}
+
+.group-card .card-popovers .gd-stat-left {
+  margin-right: 0.25rem;
+}
+
+.group-card .card-popovers .gd-stat-right {
+  margin-left: 0.25rem;
+}
diff --git a/plugins/GroupDetails/GroupDetails.js b/plugins/GroupDetails/GroupDetails.js
new file mode 100644
index 00000000..66ee9aee
--- /dev/null
+++ b/plugins/GroupDetails/GroupDetails.js
@@ -0,0 +1,318 @@
+"use strict";
+
+(function () {
+  var ROOT_ID = "root";
+  var ROUTE_PREFIX = "/groups";
+  var GROUP_METRICS_QUERY =
+    "query GroupDetailsMetrics($id: ID!) {" +
+    "  findGroup(id: $id) {" +
+    "    id " +
+    "    scenes { " +
+    "      id " +
+    "      files { duration height } " +
+    "      groups { group { id } scene_index } " +
+    "    } " +
+    "  }" +
+    "}";
+
+  var state = {
+    observer: null,
+    attachedRoot: null,
+    retryTimer: null,
+    applyingDomEnhancements: false,
+    cacheByGroupId: new Map(),
+    inFlightByGroupId: new Map(),
+  };
+
+  async function gql(query, variables) {
+    var res = await fetch("/graphql", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ query: query, variables: variables || {} }),
+    });
+    var j = await res.json();
+    if (j.errors && j.errors.length) {
+      throw new Error(
+        j.errors.map(function (e) {
+          return e.message;
+        }).join("; ")
+      );
+    }
+    return j.data;
+  }
+
+  function routeMatches() {
+    var p = window.location.pathname || "";
+    return p === ROUTE_PREFIX || p.indexOf(ROUTE_PREFIX + "/") === 0;
+  }
+
+  function parseGroupIdFromHref(href) {
+    if (!href) return null;
+    var match = String(href).match(/\/groups\/(\d+)/);
+    return match ? String(match[1]) : null;
+  }
+
+  function parseGroupIdFromCard(card) {
+    if (!card) return null;
+    var header = card.querySelector("a.group-card-header");
+    if (header && header.getAttribute("href")) {
+      return parseGroupIdFromHref(header.getAttribute("href"));
+    }
+    var firstLink = card.querySelector("a[href*='/groups/']");
+    if (firstLink && firstLink.getAttribute("href")) {
+      return parseGroupIdFromHref(firstLink.getAttribute("href"));
+    }
+    return null;
+  }
+
+  function sceneIndexForGroup(scene, groupId) {
+    var groups = (scene && scene.groups) || [];
+    var gid = String(groupId);
+    for (var i = 0; i < groups.length; i++) {
+      var g = groups[i];
+      if (g && g.group && String(g.group.id) === gid) return g.scene_index;
+    }
+    return undefined;
+  }
+
+  function isEligibleSceneIndex(idx) {
+    if (idx == null) return true;
+    var n = Number(idx);
+    return Number.isFinite(n) && n >= 0 && n <= 89;
+  }
+
+  function getSceneDurationSeconds(scene) {
+    var files = (scene && scene.files) || [];
+    var maxDur = 0;
+    for (var i = 0; i < files.length; i++) {
+      var dur = Number(files[i] && files[i].duration);
+      if (Number.isFinite(dur) && dur > maxDur) maxDur = dur;
+    }
+    return maxDur;
+  }
+
+  function getSceneVerticalPixels(scene) {
+    var files = (scene && scene.files) || [];
+    var maxHeight = 0;
+    for (var i = 0; i < files.length; i++) {
+      var h = Number(files[i] && files[i].height);
+      if (Number.isFinite(h) && h > maxHeight) maxHeight = h;
+    }
+    return maxHeight;
+  }
+
+  function computeMetrics(groupId, scenes) {
+    var totalDurationSec = 0;
+    var verticalSum = 0;
+    var verticalCount = 0;
+    var list = scenes || [];
+
+    for (var i = 0; i < list.length; i++) {
+      var scene = list[i];
+      var idx = sceneIndexForGroup(scene, groupId);
+      if (!isEligibleSceneIndex(idx)) continue;
+
+      var duration = getSceneDurationSeconds(scene);
+      totalDurationSec += duration;
+
+      if (duration > 600) {
+        var height = getSceneVerticalPixels(scene);
+        if (height > 0) {
+          verticalSum += height;
+          verticalCount += 1;
+        }
+      }
+    }
+
+    return {
+      totalDurationSec: Math.round(totalDurationSec),
+      averageVerticalPixels:
+        verticalCount > 0 ? Math.round(verticalSum / verticalCount) : null,
+      verticalSampleCount: verticalCount,
+    };
+  }
+
+  async function fetchMetricsForGroup(groupId) {
+    var data = await gql(GROUP_METRICS_QUERY, { id: String(groupId) });
+    var group = data && data.findGroup;
+    return computeMetrics(groupId, (group && group.scenes) || []);
+  }
+
+  async function getMetricsForGroup(groupId) {
+    if (!groupId) return null;
+    var gid = String(groupId);
+    if (state.cacheByGroupId.has(gid)) return state.cacheByGroupId.get(gid);
+    if (state.inFlightByGroupId.has(gid)) return state.inFlightByGroupId.get(gid);
+
+    var p = fetchMetricsForGroup(gid)
+      .then(function (metrics) {
+        state.cacheByGroupId.set(gid, metrics);
+        state.inFlightByGroupId.delete(gid);
+        return metrics;
+      })
+      .catch(function (e) {
+        state.inFlightByGroupId.delete(gid);
+        throw e;
+      });
+    state.inFlightByGroupId.set(gid, p);
+    return p;
+  }
+
+  function formatDuration(totalSeconds) {
+    var s = Math.max(0, Math.round(Number(totalSeconds) || 0));
+    var hrs = Math.floor(s / 3600);
+    var mins = Math.floor((s % 3600) / 60);
+    var secs = s % 60;
+    return hrs + ":" + String(mins).padStart(2, "0") + ":" + String(secs).padStart(2, "0");
+  }
+
+  function formatVerticalPixels(avgHeight) {
+    var n = Number(avgHeight);
+    if (!Number.isFinite(n) || n <= 0) return "n/a";
+    return String(Math.round(n)) + "p";
+  }
+
+  function buildStatNode(id, text, title) {
+    var el = document.createElement("span");
+    el.id = id;
+    el.className = "gd-stat";
+    el.textContent = text;
+    if (title) el.title = title;
+    return el;
+  }
+
+  function injectMetricsIntoCard(card, metrics) {
+    if (!card || !metrics) return;
+    var popovers = card.querySelector(".card-popovers");
+    if (!popovers) return;
+
+    var sceneCount = popovers.querySelector(".scene-count");
+    if (!sceneCount) return;
+
+    var oldLeft = popovers.querySelector(".gd-stat-left");
+    if (oldLeft && oldLeft.parentNode) oldLeft.parentNode.removeChild(oldLeft);
+    var oldRight = popovers.querySelector(".gd-stat-right");
+    if (oldRight && oldRight.parentNode) oldRight.parentNode.removeChild(oldRight);
+
+    var durationNode = buildStatNode(
+      "gd-stat-left-" + Date.now(),
+      formatDuration(metrics.totalDurationSec),
+      "Total duration for scenes with scene_index null or 0..89"
+    );
+    durationNode.classList.add("gd-stat-left");
+
+    var resolutionNode = buildStatNode(
+      "gd-stat-right-" + Date.now(),
+      formatVerticalPixels(metrics.averageVerticalPixels),
+      "Average vertical resolution for those scenes with duration > 600s"
+    );
+    resolutionNode.classList.add("gd-stat-right");
+
+    popovers.insertBefore(durationNode, sceneCount);
+    if (sceneCount.nextSibling) popovers.insertBefore(resolutionNode, sceneCount.nextSibling);
+    else popovers.appendChild(resolutionNode);
+  }
+
+  async function decorateGroupCard(card) {
+    var groupId = parseGroupIdFromCard(card);
+    if (!groupId) return;
+    var metrics = await getMetricsForGroup(groupId);
+    injectMetricsIntoCard(card, metrics);
+  }
+
+  function applyDomEnhancements() {
+    if (state.applyingDomEnhancements) return;
+    state.applyingDomEnhancements = true;
+
+    var cards = Array.prototype.slice.call(
+      document.querySelectorAll("div.group-card")
+    );
+    Promise.all(
+      cards.map(function (card) {
+        return decorateGroupCard(card).catch(function () {
+          // Ignore per-card failures so one bad response does not block others.
+        });
+      })
+    ).finally(function () {
+      state.applyingDomEnhancements = false;
+    });
+  }
+
+  function detachObserver() {
+    if (state.observer) {
+      state.observer.disconnect();
+      state.observer = null;
+    }
+    state.attachedRoot = null;
+  }
+
+  function clearRetryTimer() {
+    if (state.retryTimer) {
+      clearInterval(state.retryTimer);
+      state.retryTimer = null;
+    }
+  }
+
+  function attach() {
+    if (!routeMatches()) {
+      detachObserver();
+      return false;
+    }
+    var root = document.getElementById(ROOT_ID);
+    if (!root) return false;
+
+    if (state.attachedRoot === root && state.observer) {
+      applyDomEnhancements();
+      return true;
+    }
+
+    detachObserver();
+    state.cacheByGroupId.clear();
+    state.inFlightByGroupId.clear();
+
+    var obs = new MutationObserver(function () {
+      applyDomEnhancements();
+    });
+    obs.observe(root, { childList: true, subtree: true });
+    state.observer = obs;
+    state.attachedRoot = root;
+
+    applyDomEnhancements();
+    return true;
+  }
+
+  function scheduleAttachRetries() {
+    clearRetryTimer();
+    state.retryTimer = setInterval(function () {
+      try {
+        if (!routeMatches()) {
+          detachObserver();
+          return;
+        }
+        if (attach()) clearRetryTimer();
+      } catch (e) {
+        // Ignore transient route/render timing errors.
+      }
+    }, 500);
+    setTimeout(clearRetryTimer, 60000);
+  }
+
+  if (document.readyState === "loading") {
+    document.addEventListener("DOMContentLoaded", function () {
+      attach();
+      scheduleAttachRetries();
+    });
+  } else {
+    attach();
+    scheduleAttachRetries();
+  }
+
+  window.addEventListener("popstate", function () {
+    attach();
+    scheduleAttachRetries();
+  });
+  window.addEventListener("hashchange", function () {
+    attach();
+    scheduleAttachRetries();
+  });
+})();
diff --git a/plugins/GroupDetails/GroupDetails.yml b/plugins/GroupDetails/GroupDetails.yml
new file mode 100644
index 00000000..643e896f
--- /dev/null
+++ b/plugins/GroupDetails/GroupDetails.yml
@@ -0,0 +1,9 @@
+name: Group Details
+description: Adds group-card metrics for filtered duration and average vertical resolution.
+version: 0.1.0
+url: https://github.com/stashapp/CommunityScripts/tree/main/plugins/GroupDetails
+ui:
+  javascript:
+    - GroupDetails.js
+  css:
+    - GroupDetails.css
diff --git a/plugins/GroupDetails/README.md b/plugins/GroupDetails/README.md
new file mode 100644
index 00000000..448704e3
--- /dev/null
+++ b/plugins/GroupDetails/README.md
@@ -0,0 +1,33 @@
+# Group Details
+
+`Group Details` is a UI plugin for Stash group pages.
+
+It adds two computed metrics to each group card's stats row, flanking the scene-count element:
+
+- Left: total duration (`H:MM:SS`)
+- Right: average vertical resolution (`###p`)
+
+## Filtering rules
+
+Both metrics only consider scenes whose `scene_index` for the current group is:
+
+- `null`, or
+- an integer in the inclusive range `0..89`
+
+This excludes common trailer/bonus/out-of-band indices such as `-1`, `90`, `99`, etc.
+
+## Resolution rule
+
+Average resolution is based on vertical pixels (`height`) with an additional duration filter:
+
+- Include only eligible scenes where `duration > 600` seconds.
+- Compute as `round(sum(height) / count)`.
+- Display as `NNNp` (for example, `720p`).
+
+## Duration rule
+
+Total duration is the sum of eligible scene durations and is displayed as `H:MM:SS`.
+
+## Data source
+
+The plugin fetches group scene data through GraphQL (`findGroup`) and computes metrics in-browser. It does not rely on card DOM text parsing.