diff --git a/library/Icingadb/Model/UnreachableParent.php b/library/Icingadb/Model/UnreachableParent.php
new file mode 100644
index 000000000..de3608a3c
--- /dev/null
+++ b/library/Icingadb/Model/UnreachableParent.php
@@ -0,0 +1,181 @@
+<?php
+
+/* Icinga DB Web | (c) 2024 Icinga GmbH | GPLv2 */
+
+namespace Icinga\Module\Icingadb\Model;
+
+use Icinga\Module\Icingadb\Model\Behavior\ReRoute;
+use InvalidArgumentException;
+use ipl\Orm\Behavior\Binary;
+use ipl\Orm\Behaviors;
+use ipl\Orm\Model;
+use ipl\Orm\Query;
+use ipl\Orm\Relations;
+use ipl\Sql\Connection;
+use ipl\Sql\Expression;
+use ipl\Sql\Select;
+use ipl\Stdlib\Filter;
+
+/**
+ * Class UnreachableParent
+ *
+ * @property string $id
+ * @property int $level
+ * @property ?string $host_id
+ * @property ?string $service_id
+ * @property ?string $redundancy_group_id
+ * @property ?string $dependency_id
+ * @property int $is_group_member
+ *
+ * @property (?Host)|Query $host
+ * @property (?Service)|Query $service
+ * @property (?RedundancyGroup)|Query $redundancy_group
+ * @property (?Dependency)|Query $dependency
+ */
+class UnreachableParent extends Model
+{
+    public function getTableName(): string
+    {
+        return 'unreachable_parent';
+    }
+
+    public function getKeyName(): string
+    {
+        return 'id';
+    }
+
+    public function getColumns(): array
+    {
+        return [
+            'id',
+            'level',
+            'host_id',
+            'service_id',
+            'redundancy_group_id',
+            'dependency_id',
+            'is_group_member'
+        ];
+    }
+
+    public function createRelations(Relations $relations): void
+    {
+        $relations->belongsTo('host', Host::class)
+            ->setJoinType('LEFT');
+        $relations->belongsTo('service', Service::class)
+            ->setJoinType('LEFT');
+        $relations->belongsTo('redundancy_group', RedundancyGroup::class)
+            ->setJoinType('LEFT');
+        $relations->belongsTo('dependency', Dependency::class)
+            ->setJoinType('LEFT');
+    }
+
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new Binary([
+            'id',
+            'host_id',
+            'service_id',
+            'redundancy_group_id',
+            'dependency_id'
+        ]));
+
+        $behaviors->add(new ReRoute([
+            'hostgroup'     => 'host.hostgroup',
+            'servicegroup'  => 'service.servicegroup'
+        ]));
+    }
+
+    public static function on(Connection $db, Model $root = null): Query
+    {
+        if ($root === null) {
+            throw new InvalidArgumentException('Root node must not be null');
+        }
+
+        $query = parent::on($db);
+        $query->getSelectBase()->with(
+            self::selectNodes($db, $root),
+            'unreachable_parent',
+            true
+        )->where([
+            'unreachable_parent.level > ?' => 0,
+            'unreachable_parent.is_group_member = ?' => 0
+        ]);
+
+        return $query;
+    }
+
+    private static function selectNodes(Connection $db, Model $root): Select
+    {
+        $rootQuery = DependencyNode::on($db)
+            ->columns([
+                'id' => 'id',
+                'level' => new Expression('0'),
+                'host_id' => 'host_id',
+                'service_id' => new Expression("COALESCE(%s, CAST('' as binary(20)))", ['service_id']),
+                'redundancy_group_id' => new Expression("CAST('' as binary(20))"),
+                'dependency_id' => new Expression("CAST('' as binary(20))"),
+                'is_group_member' => new Expression('0')
+            ]);
+        if ($root instanceof Host) {
+            $rootQuery->filter(Filter::all(
+                Filter::equal('host_id', $root->id),
+                Filter::unlike('service_id', '*')
+            ));
+        } elseif ($root instanceof Service) {
+            $rootQuery->filter(Filter::all(
+                Filter::equal('host_id', $root->host_id),
+                Filter::equal('service_id', $root->id)
+            ));
+        } else {
+            throw new InvalidArgumentException('Root node must be either a host or a service');
+        }
+
+        $nodeQuery = DependencyEdge::on($db)
+            ->columns([
+                'id' => 'to_node_id',
+                'level' => new Expression('urn.level + 1'),
+                'host_id' => 'to.host_id',
+                'service_id' => 'to.service_id',
+                'redundancy_group_id' => 'to.redundancy_group_id',
+                'dependency_id' => 'dependency_id',
+                'is_group_member' => new Expression('urn.redundancy_group_id IS NOT NULL AND urn.level > 0')
+            ]);
+        $nodeQuery->filter(Filter::any(
+            Filter::equal('dependency.state.failed', 'y'),
+            Filter::equal('to.redundancy_group.state.failed', 'y')
+        ));
+
+        $nodeSelect = $nodeQuery->assembleSelect();
+
+        // TODO: ipl-orm doesn't preserve key order :'(
+        $columnsProperty = (new \ReflectionClass($nodeSelect))->getProperty('columns');
+        $columnsProperty->setAccessible(true);
+        $columnsProperty->setValue($nodeSelect, array_merge(
+            [
+                'id' => null,
+                'level' => null,
+                'host_id' => null,
+                'service_id' => null,
+                'redundancy_group_id' => null,
+                'dependency_id' => null,
+                'is_group_member' => null
+            ],
+            $nodeSelect->getColumns()
+        ));
+
+        return $rootQuery->assembleSelect()->union(
+            $nodeSelect
+                ->join(['urn' => 'unreachable_parent'], sprintf(
+                    'urn.id = %s',
+                    $nodeQuery
+                        ->getResolver()
+                        ->qualifyColumn(
+                            'from_node_id',
+                            $nodeQuery
+                                ->getResolver()
+                                ->getAlias($nodeQuery->getModel())
+                        )
+                ))
+        );
+    }
+}