diff --git a/skfem/visuals/matplotlib.py b/skfem/visuals/matplotlib.py
index fa0991e61..d1e597bda 100644
--- a/skfem/visuals/matplotlib.py
+++ b/skfem/visuals/matplotlib.py
@@ -134,11 +134,12 @@ def plot_meshline(m: MeshLine, z: ndarray, **kwargs):
         # create new figure
         fig = plt.figure()
         ax = fig.add_subplot(111)
-        xs = []
-        ys = []
     else:
         ax = kwargs["ax"]
 
+    xs = []
+    ys = []
+
     color = kwargs["color"] if "color" in kwargs else 'ko-'
     for y1, y2, s, t in zip(z[m.t[0]],
                             z[m.t[1]],