diff --git a/layout/includes/third-party/pjax.pug b/layout/includes/third-party/pjax.pug
index 38e0504..107ce2c 100644
--- a/layout/includes/third-party/pjax.pug
+++ b/layout/includes/third-party/pjax.pug
@@ -1,4 +1,4 @@
-- var pjaxExclude = 'a:not([target="_blank"])'
+- var pjaxExclude = 'a:not([target="_blank"]):not([data-fancybox])'
 if theme.pjax.exclude
   each val in theme.pjax.exclude
     - pjaxExclude += `:not([href="${val}"])`
diff --git a/package.json b/package.json
index 5debe44..f7ee6a9 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "hexo-theme-butterfly",
-  "version": "5.6.0",
+  "version": "5.6.1",
   "description": "A Simple and Card UI Design theme for Hexo",
   "main": "package.json",
   "scripts": {
diff --git a/scripts/helpers/series.js b/scripts/helpers/series.js
index bd4e65f..24bdd06 100644
--- a/scripts/helpers/series.js
+++ b/scripts/helpers/series.js
@@ -1,22 +1,24 @@
-'use strict'
-
-hexo.extend.helper.register('groupPosts', function () {
-  const getGroupArray = array => {
-    return array.reduce((groups, item) => {
-      const key = item.series
-      if (key) {
-        groups[key] = groups[key] || []
-        groups[key].push(item)
-      }
-      return groups
-    }, {})
-  }
-
-  const sortPosts = posts => {
-    const { orderBy = 'date', order = 1 } = this.theme.aside.card_post_series
-    if (orderBy === 'title') return posts.sort('title', order)
-    return posts.sort('date', order)
-  }
-
-  return getGroupArray(sortPosts(this.site.posts))
-})
+'use strict'
+
+// Read pre-built groups from tag/series.js (hexo._seriesGroups)
+// and sort each group according to the sidebar card config.
+hexo.extend.helper.register('groupPosts', function () {
+  const groups = hexo._seriesGroups || {}
+  const { orderBy = 'date', order = 1 } = this.theme.aside.card_post_series
+
+  const result = {}
+  Object.keys(groups).forEach(key => {
+    const arr = groups[key].slice() // copy to avoid mutating the shared data
+    if (orderBy === 'title') {
+      arr.sort((a, b) => {
+        const cmp = a.title.toUpperCase().localeCompare(b.title.toUpperCase())
+        return order === 1 ? cmp : -cmp
+      })
+    } else {
+      arr.sort((a, b) => order === 1 ? a.date - b.date : b.date - a.date)
+    }
+    result[key] = arr
+  })
+
+  return result
+})
diff --git a/scripts/tag/series.js b/scripts/tag/series.js
index cadd2d4..8eb9d79 100644
--- a/scripts/tag/series.js
+++ b/scripts/tag/series.js
@@ -1,67 +1,88 @@
-/**
- * series plugin
- * Syntax:
- *  {% series [series name] %}
- * Usage:
- * {% series %}
- * {% series series1 %}
- */
-
-'use strict'
-
-const urlFor = require('hexo-util').url_for.bind(hexo)
-const groups = {}
-
-hexo.extend.filter.register('before_generate', () => {
-  Object.keys(groups).forEach(k => delete groups[k])
-})
-
-hexo.extend.filter.register('before_post_render', data => {
-  if (!hexo.theme.config.series.enable) return data
-
-  const { layout, series } = data
-  if (layout === 'post' && series) {
-    if (!groups[series]) groups[series] = []
-    groups[series].push({
-      title: data.title,
-      path: data.path,
-      date: data.date.unix()
-    })
-  }
-  return data
-})
-
-function series (args) {
-  const { series } = hexo.theme.config
-  if (!series.enable) {
-    hexo.log.warn('Series plugin is disabled in the theme config')
-    return ''
-  }
-
-  const seriesArr = args.length ? groups[args[0]] : groups[this.series]
-
-  if (!seriesArr) {
-    hexo.log.warn(`There is no series named "${args[0]}"`)
-    return ''
-  }
-
-  const isAsc = (series.order || 1) === 1 // 1: asc, -1: desc
-  const isSortByTitle = series.orderBy === 'title'
-
-  const compareFn = (a, b) => {
-    const itemA = isSortByTitle ? a.title.toUpperCase() : a.date
-    const itemB = isSortByTitle ? b.title.toUpperCase() : b.date
-
-    return itemA < itemB ? (isAsc ? -1 : 1) : itemA > itemB ? (isAsc ? 1 : -1) : 0
-  }
-
-  seriesArr.sort(compareFn)
-
-  const listItems = seriesArr.map(ele =>
-    `<li><a href="${urlFor(ele.path)}" title="${ele.title}">${ele.title}</a></li>`
-  ).join('')
-
-  return series.number ? `<ol class="series-items">${listItems}</ol>` : `<ul class="series-items">${listItems}</ul>`
-}
-
-hexo.extend.tag.register('series', series, { ends: false })
+/**
+ * series plugin
+ * Syntax:
+ *  {% series [series name] %}
+ * Usage:
+ * {% series %}
+ * {% series series1 %}
+ */
+
+'use strict'
+
+const urlFor = require('hexo-util').url_for.bind(hexo)
+
+// Iterate all posts once and group by series name.
+// Result is stored on hexo._seriesGroups, shared by both tag and helper.
+function buildSeriesGroups () {
+  const groups = {}
+  const posts = hexo.model('Post').toArray()
+  for (let i = 0, len = posts.length; i < len; i++) {
+    const p = posts[i]
+    if (p.series) {
+      if (!groups[p.series]) groups[p.series] = []
+      groups[p.series].push({
+        title: p.title,
+        path: p.path,
+        date: p.date.unix()
+      })
+    }
+  }
+  return groups
+}
+
+// Build once before the first render (hexo generate / hexo server initial load).
+// before_generate runs after tag rendering, so we need this as a fallback.
+hexo.extend.filter.register('before_post_render', data => {
+  if (!hexo.theme.config.series.enable) return data
+  if (!hexo._seriesGroups) {
+    hexo._seriesGroups = buildSeriesGroups()
+  }
+  return data
+})
+
+// Rebuild after each generate cycle in hexo server to reflect latest post data.
+hexo.extend.filter.register('before_generate', () => {
+  if (!hexo.theme.config.series.enable) return
+  hexo._seriesGroups = buildSeriesGroups()
+})
+
+function series (args) {
+  const { series } = hexo.theme.config
+  if (!series.enable) {
+    hexo.log.warn('Series plugin is disabled in the theme config')
+    return ''
+  }
+
+  const groupName = args.length ? args[0] : this.series
+
+  if (!groupName) {
+    hexo.log.warn('No series specified')
+    return ''
+  }
+
+  const groups = hexo._seriesGroups || {}
+  const source = groups[groupName]
+
+  if (!source || !source.length) {
+    hexo.log.warn(`There is no series named "${groupName}"`)
+    return ''
+  }
+
+  const isAsc = (series.order || 1) === 1
+  const isSortByTitle = series.orderBy === 'title'
+
+  // .slice() to copy before sorting, so we don't mutate the shared data
+  const seriesArr = source.slice().sort((a, b) => {
+    const itemA = isSortByTitle ? a.title.toUpperCase() : a.date
+    const itemB = isSortByTitle ? b.title.toUpperCase() : b.date
+    return itemA < itemB ? (isAsc ? -1 : 1) : itemA > itemB ? (isAsc ? 1 : -1) : 0
+  })
+
+  const listItems = seriesArr.map(ele =>
+    `<li><a href="${urlFor(ele.path)}" title="${ele.title}">${ele.title}</a></li>`
+  ).join('')
+
+  return series.number ? `<ol class="series-items">${listItems}</ol>` : `<ul class="series-items">${listItems}</ul>`
+}
+
+hexo.extend.tag.register('series', series, { ends: false })