diff --git a/pkging/costello/costello.go b/pkging/costello/costello.go
index 15b8b0f..eda283e 100644
--- a/pkging/costello/costello.go
+++ b/pkging/costello/costello.go
@@ -1 +1,52 @@
 package costello
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/markbates/pkger/pkging"
+)
+
+func LoadRef(ref *Ref, pkg pkging.Pkger) error {
+	return filepath.Walk(ref.Dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		of, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		defer of.Close()
+
+		if a, ok := pkg.(pkging.Adder); ok {
+			return a.Add(of)
+		}
+
+		path = strings.TrimPrefix(path, ref.Dir)
+
+		pt, err := pkg.Parse(path)
+		if err != nil {
+			return err
+		}
+
+		if err := pkg.MkdirAll(filepath.Dir(pt.Name), 0755); err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			return nil
+		}
+		f, err := pkg.Create(pt.String())
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+
+		if _, err := io.Copy(f, of); err != nil {
+			return err
+		}
+		return nil
+	})
+}
diff --git a/pkging/costello/open.go b/pkging/costello/open.go
index 15b8b0f..563b3eb 100644
--- a/pkging/costello/open.go
+++ b/pkging/costello/open.go
@@ -1 +1,45 @@
 package costello
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/markbates/pkger/pkging"
+	"github.com/stretchr/testify/require"
+)
+
+func OpenTest(t *testing.T, pkg pkging.Pkger) {
+	r := require.New(t)
+
+	app, err := NewRef()
+	r.NoError(err)
+
+	osf, err := os.Open(filepath.Join(app.Dir, "go.mod"))
+	r.NoError(err)
+
+	osi, err := osf.Stat()
+	r.NoError(err)
+
+	osb, err := ioutil.ReadAll(osf)
+	r.NoError(err)
+	r.NoError(osf.Close())
+
+	pf, err := pkg.Open("/go.mod")
+	r.NoError(err)
+
+	psi, err := pf.Stat()
+	r.NoError(err)
+
+	psb, err := ioutil.ReadAll(pf)
+	r.NoError(err)
+	r.NoError(pf.Close())
+
+	r.Equal(osi.Name(), psi.Name())
+	r.Equal(osi.Mode(), psi.Mode())
+	r.Equal(osi.Size(), psi.Size())
+	r.Equal(osi.ModTime().Format(time.RFC3339), psi.ModTime().Format(time.RFC3339))
+	r.Equal(osb, psb)
+}
diff --git a/pkging/mem/add.go b/pkging/mem/add.go
index 12470c5..56fe549 100644
--- a/pkging/mem/add.go
+++ b/pkging/mem/add.go
@@ -25,7 +25,12 @@ func (fx *Pkger) Add(files ...*os.File) error {
 			return err
 		}
 
-		her, err := here.Package(pt.Pkg)
+		dir := f.Name()
+		if !info.IsDir() {
+			dir = filepath.Dir(dir)
+		}
+
+		her, err := here.Dir(dir)
 		if err != nil {
 			return err
 		}
diff --git a/pkging/mem/create_test.go b/pkging/mem/create_test.go
new file mode 100644
index 0000000..4ee879b
--- /dev/null
+++ b/pkging/mem/create_test.go
@@ -0,0 +1,23 @@
+package mem
+
+import (
+	"testing"
+
+	"github.com/markbates/pkger/pkging/costello"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Pkger_Open(t *testing.T) {
+	r := require.New(t)
+
+	app, err := costello.NewRef()
+	r.NoError(err)
+
+	pkg, err := New(app.Info)
+	r.NoError(err)
+
+	err = costello.LoadRef(app, pkg)
+	r.NoError(err)
+
+	costello.OpenTest(t, pkg)
+}