diff --git a/src/data_store/mod.rs b/src/data_store/mod.rs
new file mode 100644
index 0000000..cdd9e6c
--- /dev/null
+++ b/src/data_store/mod.rs
@@ -0,0 +1,22 @@
+//! Local data store
+
+use anyhow::Result;
+use camino::Utf8PathBuf;
+
+use crate::{directories::data_cache_directory, malie::models::Index};
+
+pub struct Store {
+    data_cache_directory: Utf8PathBuf,
+}
+
+impl Store {
+    pub async fn new() -> Result<Self> {
+        Ok(Self {
+            data_cache_directory: data_cache_directory().await?,
+        })
+    }
+
+    pub async fn write_index(&self, index: Index) -> Result<()> {
+        Ok(())
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 86bb5ae..09aa84c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ use clap::Parser;
 
 pub mod cli;
 pub mod constants;
+pub mod data_store;
 pub mod directories;
 pub mod editions;
 pub mod lang;
diff --git a/src/malie/client.rs b/src/malie/client.rs
index 80cbb86..68a4a8f 100644
--- a/src/malie/client.rs
+++ b/src/malie/client.rs
@@ -7,8 +7,10 @@ use tokio_stream::StreamExt;
 use tokio_util::io::StreamReader;
 use tracing::debug;
 
-use super::models::RawIndex;
+use super::models::{Index, RawIndex};
+use crate::data_store;
 use crate::directories::data_cache_directory;
+use crate::malie::models::filter_invalid_editions;
 
 /// Client to download data from mallie.io
 pub struct Client {
@@ -28,9 +30,10 @@ impl Client {
     }
 
     pub async fn download_all_data(&self) -> Result<()> {
+        let data_store = data_store::Store::new().await?;
         self.download_tcgl_index_json().await?;
         let index = self.load_tcgl_index().await?;
-        println!("{index:?}");
+        data_store.write_index(index).await?;
         Ok(())
     }
 
@@ -41,13 +44,14 @@ impl Client {
         Ok(())
     }
 
-    async fn load_tcgl_index(&self) -> Result<RawIndex> {
+    async fn load_tcgl_index(&self) -> Result<Index> {
         let file_path = self.data_cache_directory.join("tcgl_index.json");
         let index = tokio::fs::read_to_string(&file_path)
             .await
             .with_context(|| format!("Failed to read {file_path}"))?;
         let index: RawIndex =
             serde_json::from_str(&index).with_context(|| format!("Couldn't parse {file_path}"))?;
+        let index = filter_invalid_editions(index);
         Ok(index)
     }
 
diff --git a/src/malie/models.rs b/src/malie/models.rs
index 69cf4ca..0831402 100644
--- a/src/malie/models.rs
+++ b/src/malie/models.rs
@@ -10,9 +10,9 @@ use tracing::warn;
 use crate::editions::EditionCode;
 
 pub type RawIndex = HashMap<Lang, HashMap<String, RawEdition>>;
-pub type Index = HashMap<Lang, Vec<Edition>>;
+pub type Index = Vec<Edition>;
 
-#[derive(Debug, Deserialize, Eq, PartialEq, Hash)]
+#[derive(Copy, Clone, Debug, Deserialize, Eq, PartialEq, Hash)]
 pub enum Lang {
     #[serde(rename = "de-DE")]
     De,
@@ -30,14 +30,16 @@ pub enum Lang {
     Pt,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Deserialize)]
 pub struct RawEdition {
     path: String,
     #[serde(deserialize_with = "deserialize_edition_code")]
     abbr: Option<EditionCode>,
 }
 
+#[derive(Debug)]
 pub struct Edition {
+    lang: Lang,
     path: String,
     abbr: EditionCode,
 }
@@ -58,19 +60,22 @@ where
     Ok(result.ok())
 }
 
-fn filter_invalid_editions(index: RawIndex) -> Index {
+pub fn filter_invalid_editions(index: RawIndex) -> Index {
     index
         .into_iter()
-        .map(|(k, v)| {
-            let v = v
-                .into_values()
-                .map(|e| match e.abbr {
-                    Some(abbr) => Some(Edition { path: e.path, abbr }),
+        .map(|(lang, v)| {
+            let lang = lang;
+            v.into_values()
+                .map(move |e| match e.abbr {
+                    Some(abbr) => Some(Edition {
+                        path: e.path,
+                        abbr,
+                        lang,
+                    }),
                     None => None,
                 })
                 .flatten()
-                .collect();
-            (k, v)
         })
+        .flatten()
         .collect()
 }